Ebook Histopathology of the skin: Part 2

21

CHAPTER

Pigmented Purpuric Dermatosis
(Schamberg’s Disease)
Progressive pigmentary dermatosis (PPD) includes a group of conditions characterized clinically by the presence of
petechial and pigmentary macules on lower legs. The disease has a chronic and relapsing course. There is extravasation
of erythrocytes in the skin and or marked hemosiderin deposits which produces reddish brown lesions on skin. Following
clinical entities are included under the heading of pigmented purpuric dermatosis.
• Schamberg's disease (progresseive pigmented purpuric dermatosis).
• Purpura annularis telangiectodes (Majocchis disease)
• Lichen aureus.
• Pigmented purpuric lichenoid dermatosis of Gougerot and Blum
• Eczematoid like purpura of Doucas and Kapetanakis.
Other rare conditions included in the group are:
• Itching purpura of Löwenthal.
• Linear PPD.
• Granulomatous variant.
• Transitory PPD.
• Familial forms.
There are a number of drugs reported to induce PPD. They are:
• Acetaminophen.
• Aspirin.
• Adalin.
• Carbamol
• Chlordiazepoxide.
• Glipizide.
• Glybuzole.
• Hydralazine
• Meprobamate.

• Persentin.
• Reserpine.
• Thiamine.
• Interferon alfa.
• Injection Medroxy progesterone acetate.
Schamberg's Disease
(Progressive Pigmented Purpuric Dermatosis)
Schamberg's disease is characterized by asymptomatic closely set pinhead-sized reddish brown macules resembling
groups of cayenne-pepper present mainly on the lower limbs.


Pigmented Purpuric Dermatosis

127

Purpura Annularis Telangiectodes (Majocchis Disease)
The lesions are annular , bluish-red in color which initially show central red telangiectatic puncta and later on there is
atrophy. The lesions are variable in number and may involve upper extremities also.
Pigmented Purpuric Lichenoid Dermatosis
(Gougerot-Blum Syndrome)
Clinically the condition presents as plaques of various hues comprising of tiny lichenoid paplues.
Lichen Aureus (Lichen Purpuricus)
This is characterized by sudden onset of intensely itchy, localized eruption consisting of lichenoid papules in association
with purpuric lesions with a characteristic golden-brown color. The lesions are mainly present on the lower legs but trunk
and face may also be involved on rare occasions.
Itching and Eczematoid Purpura of Doucas and Kapentanakis
The lesions in this condition are more extensive and severely pruritic.
Histopathology (Fig. 21.1)
All the clinical variants of PPD have a common histopathology showing only minor differences.
• Epidermis shows mild spongiosis and exocytosis of lymphocytes (except in lichen aureus).

• Dermis shows perivascular infiltrate of lymphocytes and macrophages around superficial small blood vessels of the
skin with endothelial cell swelling and narrowing of the lumina.
• Extravasation of red blood cells with marked hemosiderin deposition in macrophages is a characteristic feature (Fig.
21.2). The degree of hemosiderin deposit is variable.

Fig. 21.1: Schamberg’s disease. Dermis shows
perivascular lymphohistiocytic infiltration and
macrophages around super-ficial and small blood
vessels

Fig. 21.2: Perl’s stain demonstrating hemosiderin
deposition in the upper dermis


128

Histopathology of the Skin

Figs 21.3A and B: Lichen aureus. Band like infiltrate is seen in the upper dermis associated
with increased dermal capillaries. Perl’s stain is positive for hemosiderin deposit (Fig. 21.3B)

Special Stains
Perl's stain is used to demonstrate iron (hemosiderin) deposition in the superficial dermis which are seen as dark blue
deposits.
Histopathological Variations Include
•
•
•

Band like infiltrate separated from the epidermis by a thin rim of uninvolved collagen and associated with increased

dermal capillaries in cases of lichen aureus (Figs 21.3A and B). In lichen aureus absence or a near absence of civatte
bodies or basal layer vacuolopathy helps in differentiating it from lichen planus.
Spongiosis and prominent neutrophils in the dermal infiltrate are seen in itching purpura.
Granulomatous infiltrate is a feature of granulomatous variant.

Differential Diagnosis
Stasis Dermatitis
In stasis dermatitis there is deposition of hemosiderin even in the deeper dermis in comparison to PPD where the
hemosiderin deposition is confined to superficial part of dermis only. Epidermal changes are more pronounced and fibrin
deposits and changes of intravascular red blood cell sludge are also features of stasis dermatitis.
Leukocytoclastic Vasculitis/Cutaneous V asculitis
Clinically the lesions in cutaneous vasculitis are erythematous papules that are palpable and do not blanch on diascopy.
Histopathology of established lesions show infiltrates of neutrophils and nuclear dust in and around venules along with
deposition of fibrin in vessel walls and occasionally in its lumen.


22

CHAPTER

Dermatitis Herpetiformis
Dermatitis herpetiformis (DH) is a condition characterized by extremely pruritic eruption comprising of symmetrical
papulovesicles, vesicles or crusts on inflamed skin, mainly involving the extensor surfaces, i.e elbows, knees, buttocks,
scapula and scalp. The papulovesicular lesions show a characteristic herpetiform grouping. There is no involvement of
the oral mucosa. Young to middle aged individuals are usually affected with a slight male predominance. In the majority
of cases (90%) there is an associated gluten-sensitive enteropathy .
Histopathology
The characteristic histopathological findings are seen in erythematous skin adjacent to early blisters. Hence, while taking
a biopsy the inclusion of perilesional skin is important.
Sequence of histopathologic changes that occurs in evolution of a lesion of dermatitis herpetiformis are:

• Accumulation of neutrophils at the tips of dermal papillae (Fig. 22.1A).
• Gradually eosinophils appear amongst neutrophils which, however, remain predominant in number.
• Formation of multiloculated blisters because of separation of tips of the dermal papillae from the overlying epidermis
(Fig. 22.1B).
• Fibrin is seen in the papillae which imparts a bluish coloration.

Fig. 22.1A: Dermatitis herpetiformis. Accumulation
of neutrophils at the tips of the dermal papilla

Fig. 22.1B: Dermatitis herpetiformis. Multilobulated
blister which is subepidermal in location


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Histopathology of the Skin

Blisters become unilocular as the rete ridges loose their attachment to the dermis as seen in clinically apparent blisters
(Fig. 22.2).
When the unilocular subepidermal blister is formed, the characteristic papillary microabscess can be observed at the
periphery of the blister.
Prominent inflammatory infiltrate of neutrophils and some eosinophils is seen in the dermis beneath the papillae.
Leukocytoclasis of several neutrophils can be seen.
Apoptotic keratinocytes may be a chance finding seen above the papillary microabscesses.

Immunofluorescence Testing
Direct immunofluorescence (DIF) test shows granular deposits of IgA in the dermal papillae of perilesional and uninvolved
skin, although the deposition is not uniform. The deposition is maximum in normal skin adjacent to an active lesion.
Fibrillar IgA deposits may also be present.
Other immunoglobulins particularly IgM can be seen in 30 percent and C3 in approximately 50 percent of cases.
Early in the course of the disease IgA deposits may be absent and a repeat DIF should then be performed.
Epidermolysis Bullosa Acquisita
Epidermolysis bullosa acquisita (Dermolytic pemphigoid, EBA) is a rare, non- hereditary subepidermal bullous disorder
characterized by acquired fragility of skin. In the classical form bullae develop on non-inflammatory bases in areas prone
to minor trauma such as acral areas.The bullae heal with scarring and milia formation.A characteristic nail dystrophy and
alopecia are other features present. This form is associated with malignant lymphoma, amyloidosis and colitis or enteritis.
Some patients have marked involvement of oral and conjunctival mucosa in addition to acral lesions and nail dystrophy
.
These cases resemble cicatricial pemphigoid (cicatricial pemphigoid-like).
In other cases the bullae may arise on pruritic, erythematous macules and papules, the lesions being more generalized
and not entirely acral in location (bullous pemphigoid-like).
Histopathology Shows (Fig. 22.3)
•
•

Subepidermal bulla with fibrin and only a few inflammatory cells in the bullous cavity.
The roof of the blister is well preserved with few dermal fragments attached to the epidermis.

Fig. 22.2: Dermatitis herpetiformis. Unilocular subepidermal bulla containing predominantly neutrophils

Fig. 22.3: Epidermolysis bullosa acquisita. Subepidermal bulla with fibrin and only a few
inflammatory cells in the bullous cavity


Dermatitis Herpetiformis

•
•
•

131

Dermal changes depend upon whether the bullae are inflammatory (arising on inflamed skin) or non-inflammatory
(arising on normal skin).
In non-inflammatory lesions sparse lymphocytic infiltrate is seen around the vessels of the superficial vascular plexus.
In inflammatory lesions dense inflammatory infiltrate comprising predomi-nantly of neutrophils is present in the upper
dermis. Few eosinophils may also be seen.

Immunofluorescence Testing
DIF (Direct immunofluorescence test): Perilesional skin shows linear deposition of immunoglobulins particularly IgG and
of complement at the basement membrane zone in the vast majority of cases. IgM and IgA may also be present as well.
A deposition of only linear C3 at the dermoepidermal junction favors the diagnosis of bullous pemphigoid and when
multiple immunoglobulin subclasses (IgG, IgM and IgA) are present at the dermoepidermal junction, then the diagnosis is
more likely of EBA. DIF may not reliably help to differentiate bullous pemphigoid from EBA.
Indirect immunofluorescence (IIF) test: Circulating anti-basement membrane zone antibodies are seen in upto 50 percent
cases of EBA.
Salt-split technique is a more reliable test and exact diagnosis can be made in majority of cases. The antibodies in EBA
are directed against type VII collagen antigen a major component of anchoring fibrils and hence on salt-split skin studies
IgG is demonstrated on the floor and not on the roof of the split.
In bullous pemphigoid, localization of antibodies only to the floor of the blister is not a feature. They are demonstrated
either only on the roof of the blister or both on the roof and floor of the subepidermal blister .
Cicatricial Pemphigoid
(Benign Mucous Membrane Pemphigoid)
Cicatricial pemphigoid (benign mucous membrane pemphigoid) is an uncommon, chronic, vesiculo-bullous disease
characterized by its chronic course, its scarring nature and its predilection for the mucosal surfaces. Cutaneous lesions
occur in about 25 percent of cases but only in 10 percent it is the initial clinical presentation. There is a tendency for

blister to recur in the same area.
The most commonly involved mucosal surfaces in the order of frequency , are the oral mucosa, the conjunctiva, the
larynx, the genitalia and the esophagus. Two types of cutaneous lesions are seen. In one type there are scattered tense
bullae that heal without scarring. In the other type recurring blisters develop on one or several areas of erythema and heal
with scarring.
Localized Cicatricial Pemphigoid (Brunsting-Perry T ype)
In this type of cicatricial pemphigoid there are no mucosal lesions but there are one or several circumscribed erythematous
patches on which recurrent crops of blisters appear. Ultimately atrophic scarring results. Usually patches are confined to
the head and neck.
Histopathology
Subepidermal bulla is seen.
Dermal infiltrate depends upon the age of the lesion. Very early lesions show predominance of neutrophils and
neutrophilic abscess. As the lesions age, number of eosinophils increases and in older lesions there are more of
lymphocytes and less number of neutrophils.
• Eosinophils are always fewer in number in comparison to that seen in bullous pemphigoid.
• Newly formed collagen bundles are seen in areas of scarring. These are arranged parallel to the surface instead of
normal haphazard arrangement.
• The presence of a sebaceous gland within the blister is regarded as an important feature in the diagnosis of cicatricial
pemphigoid. This results from extension of the bulla along the edge of the pilosebaceous unit.
Occasionally it may be impossible to differentiate cicatricial pemphigoid from bullous pemphigoid and dermatitis
herpetiformis on histopathologic examination.
•
•


132

Histopathology of the Skin

Direct Immunofluorescence (DIF) T est

Linear deposits of IgG and C3 are seen along the basement membrane zone in approximately 80 percent of cases.
IgA and other immunoglobulins may be detected in approximately 20 percent of cases but only rarely is IgA the only
immunoglobulin present.
Herpes Gestationis (Pemphigoid Gestationis)
Herpes gestationis is a rare pruritic, vesiculo-bullous dermatosis that usually develops during the second to third trimester
of pregnancy. Initial lesions are pruritic urticarial plaques that usually develop in the periumblical area.
The lesions
gradually involve the extremities, hands and feet and progress to form tense vesicles, bullae and few herpetiform lesions.
The disease tends to recur with subsequent pregnancies and the lesions get exacerbated during menstrual period and by
oral contraceptives.
Histopathology
Early urticarial plaques show:
• Marked edema of the papillary dermis.
• Superficial and mid-dermal perivascular infiltrate of lymphocytes, histiocytes and eosinophils.
• Spongiosis which may be eosinophilic in nature is often seen overlying the tips of the dermal papillae.
• Focal necrosis of the basal keratinocytes which lead to subepidermal blister is evident in clinically vesiculo-bullous
lesions.
• Subepidermal bulla contains eosinophils, lymphocytes and histiocytes.
DIF (Direct Immunofluorescence) test: Linear deposition of C3 and sometimes IgG along the basement membrane zone
is seen in perilesional skin.
Bullous Systemic Lupus Erythematosus
Vesiculo-bullous lesions in patients with systemic lupus erythematosus are non-itchy, widespread and occasionally show
predilection for sun exposed areas of the body .
Histopathology
Three different histopathologic patterns are described:
• Dermatitis herpetiformis like with subepidermal splitting and papillary micro abscesses The neutrophils and nuclear
dust are present deeper in the papillary dermis around vessels which is usually not seen in dermatitis herpetiformis.
• Histopathologic pattern showing marked basal layer vacuolization that leads to subepidermal blister.
• There may be vasculitis with subepidermal blister and pustule formation.
DIF (Direct immunofluorescence) test: IgG and C3 deposition at the epidermal basement membrane zone. IgM and IgA

are seen in 50 percent and 60 percent of cases respectively . The linear pattern of deposition is more common (50%) as
compared to granular “band like pattern” (25%).
Epidermolysis Bullosa
Epidermolysis bullosa (EB) comprises a group of genetically determined skin fragility disorders characterized by blistering
of the skin and mucosa following mild mechanical trauma. Mechanobullous disease is an alternative term used for these
disorders. These mechanobullous diseases are classified on the basis of the level of the split.
• Epidermolytic (Epidermolysis bullosa simplex and its subtypes).
• Junctional (Junctional epidermolysis bullosa and its subtypes)
• Dermolytic (Dystrophic epidermolysis bullosa and its subtypes).


Dermatitis Herpetiformis

133

Histopathology
A definitive diagnosis of various types and subtypes of epidermolysis bullosa cannot be made on routine light microscopy
.
Routine histopathology in majority of variants of EB shows:
• Subepidermal blister.
• Scanty inflammatory infiltrate.
Histochemical staining is required for the diagnosis of various types of epidermolysis bullosa.
Darier-White Disease (Keratosis Follicularis) and Acral Darier- White Disease
(Acrokeratosis verruciformis of Hopf)
Darier White disease (DWD) is an autosomal dominant disorder characterized by abnormal keratinization of the epidermis,
nail and mucous membranes.The cutaneous lesions are discrete, scaly, waxy, crusted papules that are usually malodorous,
and are commonly seen on the face, forehead, scalp, chest and back. The lesions are more severe in summer . Punctate
keratosis on the palms and soles occur in most patients.
The nails are fragile and there is a characteristic V-shaped
scalloping of the free edge and subunqual thickening.White centrally depressed papules are often seen on the mucosa of

the cheeks, palate and gums and may involve the rectum and vulva. Multiple plane keratosis on the dorsa of hands
(acrokeratosis verruciformis) are a common finding.
Histopathology Shows (Fig. 22.4)
•
•
•
•

•
•

Acanthosis, hyperkeratosis and papillomatosis.
Lacunae, which are small, slit like intraepidermal vesicles present directly above the basal cell layer . They contain
acantholytic cells.
There is irregular upward proliferation into the lacunae of papillae lined by a single layer of basal cells or so-called villi
.
The most characteristic feature is the presence of corps ronds and grains. The corps ronds and grains are seen in the
upper startum malpighii specially in the granular and horny layer . They possess a central homogenous, basophilic
pyknotic nucleus that is surrounded by a clear halo. Peripheral to the halo lies basophilic dyskeratotic material as a
shell.
Grains are seen in the horny layer and as acantholytic cells within the lacunae. They resemble parakeratotic cells but
are somewhat lar ger.
Dermis shows a chronic inflammatory infiltrate.


Fig. 22.4: Darier’s-White disease showing
suprabasal lacunae, corps ronds and grains


134

Histopathology of the Skin


Fig. 22.5: Hailey-Hailey disease showing suprabasal
bulla with villi formation and acantholytic cells

Hailey-Hailey Disease (Benign Familial Pemphigus)
Hailey-Hailey disease (HHD) is an autosomal dominant condition characterized by late onset (aged 20-30 years) of painful
erosions, vesiculopustules and scaly erythematous plaques at the sites of friction such as the neck, axillae, groins and
perineum. Mucosal involvement is not common.
Histopathology (Fig. 22.5)
The histopathologic findings in HHD are similar to Darier-White disease (DWD) in that there is acantholysis with epidermal
clefting and vesiculation but the acantholysis is more pronounced in DWD.
Diabetic Bulla
Cutaneous disorders associated with diabetes mellitus are thought to occur in about one-third of patients during the
course of their disease. Three cutaneous disorders usually considered diagnostic of diabetes are :
• The syndrome of limited joint mobility and waxy skin.
• Diabetic dermopathy.
• Diabetic bulla.
Diabetic bullous lesions are usually recurrent in nature and most commonly affect the acral areas especially the feet.
Histopathology
•
•
•

Intraepidermal cleavage without acantholysis situated in the superficial part of the epidermis is the most commonly
seen histopathological finding.
Subepidermal bulla may be seen in some cases.
Dermal papillary blood vessels may show slight thickening.

Differential Diagnosis Includes
•
•
•
•
•

Bullous pemphigoid.
Epidermolysis bullosa acquisita.
Porphyria cutanea tarda.
Erythema multiforme.
Drug eruption.


23

CHAPTER

Sarcoidosis
Sarcoidosis is a systemic disease with involvement of multiple organs including skin. In many cases cutaneous lesions
may be the only presenting manifestation. Between 10 to 35 percent of patients with systemic sarcoidosis exhibit cutaneous
lesions.
The skin lesions in sarcoidosis can be categorized as:
• Specific : Showing a granulomatous histology and
• Non-specific.
Specific Lesions
The specific lesions are varied in morphology comprising of papules, nodules, plaques, subcutaneous tumors and scaly
erythematous and atrophic flat lesions. The skin lesions because of their characteristic varying color hues and a waxy
translucent appearance usually prompts the diagnosis of sarcoidosis. They are almost never pruritic or painful.

Maculopapular sarcoidosis is a term used for flat-topped translucent reddish to brownish papules seen around eyes
and nasolabial folds. Papules when present in annular configuration simulate, granuloma annulare.
Annular lesions are also
produced by plaque type lesions that undergo central atrophy simulating necrobiosis lipoidica.
Subcutaneous sarcoidosis (Darier-Roussy) usually presents as nodules which are usually not translucent, have a
violaceous hue and are commonly seen on extremities and trunk.
Plaques of sarcoidosis may show large telangiectatic vessels on the surface– angiolupoid lesions and the term lupus
pernio is used for plaque lesions present on the ear lobes, nose, fingers and toes.
Tumor like lesions may be confused with cutaneous T cell lymphomas (CTCL).
Scarring alopecia, widespread erythema and hypopigmented macules are infrequent manifestations.
Non-specific Lesions
Erythema nodosum is a non-specific skin lesion of sarcoidosis which when present is an indicator of the benign selflimiting course of the disease.
Histopathology (Specific Lesions)
•
•
•

Epidermis is usually normal or atrophic Verrucous lesions show acanthosis. Prominent hyperkeratosis is seen in
ichthyosiform variant.
Sarcoidal granulomas are discrete, round or oval localized either in the superficial dermis or they may extend through
the whole thickness of the dermis or subcutis depending on the type of cutaneous lesion biopsied.
Sarcoidal granulomas are composed predominantly of epithelioid histiocytes and multinucleate giant cells which may
be either Langhan's or foreign body type. They are referred to as naked granulomas because of lack of notable mantle
of lymphocytes around the granulomas and absence of caseous necrosis. They may, however, be surrounded by a
sparse rim of lymphocytes and plasma cells and only on rare occasions lymphocytes are present within them (Fig.
23.1).


136

Histopathology of the Skin


Fig. 23.1: Sarcoidosis. Naked granulomas are seen in the
dermis, lacking notable mantle of lymphocytes around the
granulomas and absence of caseous necrosis

•

Inclusions ie asteroid bodies (eosinophilic star shaped bodies) or Schaumann’
s bodies (basophilic laminated concentric
whorls) may be observed within the histiocytes. They are characteristic but not specific feature of sarcoidosis (Fig.
23.2).

Subcutaneous Sarcoidosis
Histopathology
• Granulomas predominantly involve fat lobules with some involvement of fibrous septa.
• Dense lymphocytic infiltrate often surround granulomas.
• Slight necrosis can be seen in the center of some granulomas.
• Asteroid bodies or Schaumann’s bodies may be seen within epithelioid histiocytes. Occasionally granulomas may be
seen within the dermis.


Fig. 23.2: Sarcoidosis. Asteroid bodies
seen in a epithelioid histiocyte


Sarcoidosis

137


Fig. 23.3: Sarcoidosis. Reticulin stain demonstrating
network of reticulin fibers surrounding and
permeating the sarcoidal granulomas

Special Stains
Reticulin stains demonstrate a network of reticulin fibers surrounding and permeating the histiocytic cluster (Fig. 23.3).
Conditions other than sarcoidosis that may rarely show sarcoidal granulomas are:
• Blau’s syndrome.
• Foreign body reactions.
• Secondary syphilis.
• Sezary syndrome.
• Herpes zoster scars.
• Systemic lymphomas.
• Common variable immunodeficiency.


24

CHAPTER

Lupus Erythematosus (LE)
Lupus erythematosus is an autoimmune disease with clinical presentation ranging from a skin rash unaccompanied by
extracutaneous stigmata to one comprising of progressive multisystem disease. Discoid lupus erythematosus (DLE) with
predominantly cutaneous lesions represents one end of the spectrum and systemic lupus erythematosus (SLE) with lifethreatening manifestations of nephritis, central nervous system disease and vasculitis forms the other extreme end.The
pattern and type of skin involvement to a great extent gives an indication of the position of patient in the spectrum.
The cutaneous lesions of lupus erythematosus are classified into LE specific lesions and LE non-specific skin lesions.
LE specific skin lesions show the characteristic histopathological features of LE and include three subtypes:
• Acute cutaneous lupus erythematosus (ACLE).

• Subacute cutaneous lupus erythematosus (SCLE).
• Chronic cutaneous lupus erythematosus (CCLE).
LE non-specific skin lesions do not show the characteristic histopathology of LE and/ or may be seen as a feature of
another disease process.
The diagnosis of systemic lupus erythematosus is based on following 1 1 criteria which combines both clinical and
laboratory parameters.
• Malar rash.
• Discoid rash.
• Photosensitivity.
• Oral ulcers, usually painless.
• Arthritis, nonerosive, involving two or more peripheral joints with tender-ness, swelling or effusion.
• Serositis (pleurisy or pericarditis).
• Renal disorder (persistent proteinuria exceeding 0.5 g/day or cellular casts).
• Neurologic disorders (seizures or psychosis).
3
• Hematologic disorder (hemolytic anemia, leukopenia of less than 4000/cu mm
or lymphopenia of less than 1500/mm3
or thrombocytopenia of less than 100,00/mm 3).
• Immunologic disorder (positive LE-cell preparation, anti-DNA antibody in abnormal titer , antibody to Sm nuclear
antigen or false positive serologic test for syphilis).
• Antinuclear antibody (ANA).
A diagnosis of systemic lupus erythematosus is based on the presence of serially or simultaneously any four or more
of the above mentioned-11 criteria.A diagnosis of SLE is also indicated in any patient who has three of the following four
manifestations.
• LE specific skin lesions.
• Renal involvement.
• Serositis.
• Joint involvement.
In cutaneous lupus erythematosus histopathological findings may not be sufficient to correctly assess the sub-type of
LE.

Lupus Erythematosus (LE)

139

Chronic Cutaneous Lupus Erythematosus
(Discoid Lupus Erythematosus)
Classic DLE
In classic DLE the lesions are well-defined coin shaped (i.e. discoid) erythematosus plaques covered by a prominent
adherent scale that extends into the orifices of dilated hair follicles. When the adherent scale is lifted from an established
lesion, keratotic spikes similar in appearance to carpet tacks can be seen to project from the undersurface of the scale (the
“carpet tack” sign). The discoid lesions typically develop peripheral erythema and hyperpigmentation with central atrophic
scarring and telangiectasia.
The common sites involved in classic DLE are face, scalp, ears, V-area of the neck and extensor aspect of upper
extremity. Nasolabial folds are usually not involved. Localized DLE lesions are confined to head and neck whereas in
generalized or disseminated DLE, lesions occur both above and below the neck.
DLE lesions below the neck may involve any part of the body, but are commonly seen on the extensor aspects of the
upper arms, forearms and hands.
Involvement of the scalp may lead to irreversible scarring alopecia. This is different from reversible non-scarring
alopecia seen in patients with SLE (lupus hair) which is a form of telogen effluvium because of flaring up of systemic
illness. Various changes are also seen in the nail unit.
Uncommon clinical variants of chronic cutaneous LE include:
• Follicular DLE.
• Erosive DLE.
• Mucosal DLE.
• Hypertrophic DLE (hyperkeratotic or verrucous DLE).
• Rubric lupus planus (overlapping features of hypertrophic LE and lichen planus.
• Linear DLE.
Histopathology of Classic DLE (Figs 24.1A and B)

•

Hyperkeratosis with follicular plugging. Follicular channels in the dermis are usually filled with concentric layers of
keratin instead of hair.

Figs 24.1A and B: DLE. There is follicular plugging and moderate to heavy superficial and deep
perivascular lympho-histiocytic infiltrate with hydropic degeneration of the basal cells


140
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•
•

Histopathology of the Skin

Thining and flattening of the stratum malpighii. Pronounced acanthosis when seen reflects greater lesional age
(hypertrophic DLE).
Hydropic degeneration of basal cell layer also referred to as liquifaction degeneration is seen as vacuolated spaces
beneath and between basilar keratinocytes. This is considered to be an important histopathological feature and in its
absence, a diagnosis of lupus erythematosus should be made with caution.
Basilar keratinocytes may show individual cell necrosis (apoptosis) and apoptotic cells referred to as colloid bodies
may be seen in the lower epidermis or in the papillary dermis. They are round to oval homogenous, eosinophilic
structures measuring approximately 10 μm in diameter.

Conditions characterized by colloid bodies:
Lupus erythematosus.
Lichen planus.
Poikiloderma.
Fixed drug eruption.

Lichenoid keratosis.
•
•
•
•
•

Squamatization of basilar keratinocytes (basilar keratinocytes assume elongated contours like their superficial counterparts
instead of retaining their normal columnar appearance) is seen.
Thickening and tortuosity of basement membrane is best appreciated with Periodic Acid-Schiff (PAS) stain (Fig.
24.2). In areas showing marked hydropic degeneration of the basal cells, the P AS-positive subepidermal basement
zone may be inconspicuous or fragmented.
Dermis shows moderate to heavy superficial and deep perivascular and periappendageal lymphocytic infiltrate. The
infiltrate is also seen along the dermo-epidermal junction and in an interstitial pattern.
Slight extension of the inflammatory infiltrate into subcutaneous fat may be seen. Other dermal changes include
edema, vasodilatation, slight extravastion of erythrocytes and interstitial mucin deposition.
Pronounced dermal mucin deposition is usually present in lesions of DLE and is a useful discriminating feature from
other conditions like nodular lymphocytoma cutis, drug or arthropod bite reaction, which also exhibit prominent
dermal lymphocytic infiltrate.


Fig. 24.2: DLE. PAS st ain shows thickening
and tortuosity of the basement membrane


Lupus Erythematosus (LE)

141

Folliculotropic DLE

This term is used to designate lesions of DLE showing perifollicular and perivascular inflammation without an accompanying
inter follicular interface dermatitis. Histopathologically such cases may be difficult to differentiate from Jessner's lymphocy
tic
infiltrate of skin and delayed hypersensitivity reactions. Features favoring the diagnosis of folliculotropic DLE includes:
• Presence of mucin in the dermis.
• Absence of tissue eosinophilia.
• Evidence of follicular epithelial destruction.
Verrucous Lupus Erythematosus
Verrucous lupus erythematosus is a subset of LE characterized by verrucous lesions that may resemble lichen planus or
keratoacanthoma. The presence of lesions typical of DLE elsewhere helps in making the diagnosis.
Histopathology (Fig. 24.3)
• Hyperkeratosis
• Acanthosis.
• Papillomatosis.
• Lower epidermis shows fairly large number of dyskeratotic keratinocytes.
• Band like mononuclear infiltrate along the dermo-epidermal junction.
Lesions resembling keratoacanthoma exhibit:
• Cup shaped keratotic filled crater.
• Acanthotic epidermis with elongated rete ridges surround the cup shaped crater .
• Dermis shows sparse mononuclear infiltrate.
The features that help in making the diagnosis include:
• Deep dermal perivascular, periappendageal and interstitial infiltrate.
• Deposit of mucin in the dermis.
Rare Subtypes of LE Specific Skin Disease
LE Panniculitis/ LE profundus:
LE panniculitis /LE profundus are uncommon variants of CCLE where the inflammation is confined to subcutaneous
tissue and the deeper dermis. About 70 percent of these patients also have associated typical lesions of DLE.
The term LE panniculitis refers to those cases where there is only involvement of the subcutaneous fat and the term
LE profundus is used for those cases who have both panniculitis and DLE lesions.

Fig. 24.3: Verrucous DLE. There is marked hyperkeratosis, moderate acanthosis,
papillomatosis with almost band like mononuclear infiltrate at the dermoepidermal junction


142

Histopathology of the Skin

Clinically LE panniculitis presents as subcutaneous nodules 1-3 cm in diameter. The surface of the nodules may show
deep saucerized depression produced by attachment of the skin to the underlying subcutaneous nodules.
Histopathology
•
•
•

Lobular lympho-histiocytic infiltrate often with plasma cells.
Vascular changes include endothelial prominence, thrombosis, calcification or perivascular fibrosis ("onion skin"
appearance).
Stromal mucin deposit may be prominent in well-established lesions.

Chilblain LE/Perniotic LE
Chilblain LE lesions as their name implies are initially similar to lesions seen in idiopathic chilblain comprising of purplish
red patches, papules, plaques involving toes, fingers and face. These lesions have a tendency to be precipitated by
exposure to cold and ultimately they evolve into scarred atrophic plaques associated with telangiectasia resembling old
lesions of DLE. There may be lesions of classic DLE on the face and head.
Histopathology
•
•

Superficial and deep perivascular lymphocytic infiltrate.

Fibrin deposition in reticular dermal based blood vessels.

Lupus Erythematosus Tumidus (LET, Tumid LE)
Tumid LE is characterized by succulent, edematous plaques with minimal surface change. These lesions tend to resolve
completely without either scarring or atrophy .
Histopathology
•
•

Histopathological changes are predominantly dermal. The characteristic epidermal histologic changes of LE specific
skin disease are usually not seen.
Dermal changes include excessive mucin deposition and superficial and deep dermal perivascular , interstitial and
periappendageal lymphocytic infiltrates.

SUBACUTE CUTANEOUS LUPUS ERYTHEMATOSUS
Subacute lupus erythematosus which represents 9 percent of all cases of lupus erythematosus manifest predominantly as
photodistributed erythematous symmetric non-scarring eruption occurring in isolation or accompanied by usually mild
extracutaneous manifestation. The head and neck area is uncommonly involved. Two types of skin lesions are seen:
• Papulosquamous and/or
• Annular polycyclic.
An individual who has significant extracutaneous pathology especially in the context of renal and central nervous
system disease should not be classified as having SCLE. In the elderly SCLE is frequently trigged by drug therapy , the
main implicated drugs being thiazides and calcium channel blockers.
Histopathology (Fig. 24.4)
•

Lymphocytic interface dermatitis with suprabasilar exocytosis of lympho-cytes showing satellitosis to degenerating
keratinocytes and colloid body formation.
• Hybrid pattern of interface dermatitis is seen in SCLE which refers to alternating zones of band-like lichenoid infiltrate
and cell-poor basal cell vacuolar alteration.

• Follicular plugging is not a prominent feature.
• Deep perivascular or periappendageal infiltrate is not significant.
The distinguishing features from lichen planus include:
Parakeratosis
Areas of granular cell dimunition.


Lupus Erythematosus (LE)

143


Fig. 24.4: SCLE. There is lymphocytic interface
dermatitis with prominent subepidermal edema

Prominent lymphocytic satellitosis around necrotic spinous layer keratinocytes.
Hybrid morphology of the interface dermatitis.
• Deeper perivascular extension and/or tissue eosinophilia usually points towards drug-based etiology.
• Basement membrane zone thickening in SCLE is of greater magnitude as compared to SLE but is not as pronounced
as that seen in DLE.
Neonatal lupus erythematosus has clinical, histologic and serological changes similar to SCLE.
• Mucin deposition in the dermis is a prominent feature seen in SCLE which distinguish it from other causes of
atrophying lichenoid dermatitis, i.e. atrophic lichen planus and lichenoid drug eruption.
Patients with MCTD (mixed connective tissue disease) can develop a rash simulating SCLE clinically as well as
histopathologically.
SYSTEMIC LUPUS ERYTHEMATOSUS
A diagnosis of systemic lupus erythematosus (SLE) is based on the criteria laid down by the
American College of
Rheumatology (ACR).SLE usually has its onset in early to middle adulthood with peak age of onset being in the fourth
decade of life. Females represent over eighty percent of all cases. Initially only 15 percent of patients present with skin

lesions, articular complaints being the main presenting feature. With time, however, 80 percent of patients manifest with
skin involvement. The most common skin presentation is the faint photodistributed erythema and a malar " butterfly rash"
with fine scaling. Bullous SLE and Rowell's syndrome (coexistence of SLE and erythema multiforme) are rare forms of
SLE. Few patients of SLE may have skin lesions simulating annular lesions of subacute lupus erythematosus (SCLE) and
discoid lesions seen in discoid lupus erythematosus (DLE).
Vasculopathic lesions commonly seen in SLE are in the form of:
• Palpable purpura
• Ulcers
• Digital infarcts
• Perniotic lesions of the fingers and toes (chilblain lupus erythematosus)
• Urticarial lesions including urticarial vasculitis.
Histopathology (Cell-poor interface dermatitis,
“invisible dermatosis”)
•
•

The cornified layer usually exhibits patchy parakeratosis but can be normal.
Epidermis is unaltered, although thinning of epidermis with loss of rete ridges may be an occasional finding.


144

Histopathology of the Skin

•
•
•

Colloid bodies are often present.
There is minimal vacuolization of basal cell layer.

The lympho-histiocytic infiltrate is relatively sparse in the form of focal lymphocytes tagging along the dermoepidermal junction.
• Basement membrane thickening and follicular plugging is usually not seen.
• The most conspicuous feature is the presence of pronounced mucinosis of the dermis which can be appreciated even
at a light microscopic level in hematoxylin and eosin preparations as beaded basophilic globules and strings between
and adherent to the collagen bundles.
• Special stains, i.e. colloidal iron or alcian blue may be employed to highlight these deposits which take up blue color
with these stains.
Demonstration of dermal mucinosis is a most significant finding that favour a diagnosis of SLE over other causes of
cell poor interface dermatitis such as a morbilliform drug reactions and viral exanthemas.
Subcutaneous fat is often involved in SLE in the form of mucin deposition, lymphocytic infiltrate, edema and fibrinoid
deposits that may separate the adipocytes.
Differential Diagnosis: Lichen Planus
Histopathologically DLE has to be differentiated from lichen planus as both show prominent interface dermatitis. The
differentiating features are summarized in Table 24.1.
Table 24.1: Histopathological difference between DLE and Lichen planus
DLE

Lichen planus

Epidermis frequently flattened.
No saw-toothing of rete ridges.
Dermal infiltrate is both superficial and deep
Stromal mucin deposit is an important diagnostic feature.

Wedge shaped hypergranulosis
Saw-toothing of rete ridges.
Dermal infiltrate is superficial.
No stromal mucin deposition.

There are five conditions that show patchy dermal lymphocytic infiltrations:

• Lupus erythematosus.
• Lymphocytic lymphoma.
• Lymphocytoma cutis.
• Polymorphic light eruption of the plaque type.
• Lymphocytic infiltration of the skin of Jessner .
In the absence of significant subepidermal vacuolization LE must be differentiated from the other four diseases (Table
24.2).
Table 24.2: Conditions show patchy dermal lymphocytic infiltrations dif fer from LE
Jessner's lymphocytic
infiltration of the skin

Lymphocytoma
cutis

Polymorphic light
eruption (plaque type)

Lymphocytic lymphoma

The dermal infiltrate may be indistinguishable from that seen in early
non-scarring or purely dermal lesions
of lupus erythematosus
No interface changes as seen
in LE.
Negative immunofluorescence
findings of skin.
(In LE immunofluorescence
findings are positive in 90%
of cases)

Lymphocytic infiltrate is
heavier than in LE.
May have an interstitial
component.
Shows no tendency to arrange
itself around pilosebaceous
structures.
Often contains an admixture of
larger, paler lymphocytes arranged
in lymphoid follicles simulating
germinal center formation.

Prominent band of papillary
dermal edema.
Lymphocytic infiltrate is more
dense in superficial than in deep
dermis and is occasionally
admixed with neutrophils
There is no folliculocentric
arrangement of infiltrate.
Absence of stromal mucin
deposition.

Atypical lymphocytes seen which are
tightly packed and have an interstitial
distribution (“Indian filing”) and do
not surround pilosebaceous units (as
in LE).

Lupus Erythematosus (LE)

145


Fig. 24.5: Dermatomyositis. There is epidermal atrophy, vacuolar
degeneration of the basal cell layer, dilatation of the superficial
blood vessels with edema of the upper dermis

Dermatomyositis
Dermatomyositis is a clinical condition where there are inflammatory changes in skin associated with non-suppurative
myositis (polymyositis). Cutaneous lesions may develop before the onset of muscle involvement upto 2 years or more.
Amyopathic dermatomyositis is characterized by absence of clinical or laboratory evidence of muscle disease for at
least 2 years after the onset of cutaneous lesions.
Cutaneous lesions commonly seen in dermatomyositis are:
• Violaceous or erythematous slightly scaly lesions present on face, shoulders, extensor surface of forearms and thighs.
• Poikiloderma (telangiectasias, hyperpigmentation and hypopigmentation)- may be seen.
• Heliotropic rash- purplish discoloration and edema of periorbital tissues.
• Gottron's papules- atrophic papules and plaques over the knuckles.
Histopathology (Fig. 24.5)
Histologic features are inconsistent and variable. At times minimal changes are seen on histopathology:
• Sparse superficial perivascular infiltrate of lymphocytes
• Variable edema and mucinous change in the upper dermis.
More frequently encountered histologic changes are:
• Vacuolar degeneration of the basal cell layer.
• Rare presence of Civatte bodies, few neutrophils in papillary dermis and around superficial vessels particularly in
association with fibrinoid change.
• Thickening of basement membrane.
Additional features that can be seen are:
• Epidermal atrophy.

• Melanin incontinence.
• Dilatation of superficial vessels (poikilodermatous change).
Histopathology of Gottron's papules:
• Mild hyperkeratosis.
• Acanthosis.
• Basal vacuolar changes.
Presence of subepidermal vesiculation indicates the occurrence of under -lying internal malignancy.


25

CHAPTER

Pyoderma Gangrenosum
Pyoderma gangrenosum (PG) is an uncommon destructive ulceration characterized by a pustule or nodule on an
erythematous base, which is extremely painful and which rapidly progresses to become a necrotic ulcer with a characteristic
ragged, undermined violaceous edge. Pyoderma gangrenosum demonstrates pathergy a condition generally defined as the
induction of a lesion by limited trauma or inflammation of the skin. The ulcer usually rapidly enlarges to a size of 10 cm
or more in diameter.
Pyoderma gangrenosum has a predilection for the lower extremities but other areas of body may also be involved.
In more than 50 percent of cases, pyoderma gangrenosum is associated with other diseases like inflammatory bowel
disease, hematological disorders including acute lymphoid and myeloid leukemias and myeloma, rheumatological conditions
including rheumatoid arthritis and lupus erythematosus and hepatopathies including chronic active hepatitis, primary
biliary cirrhosis, and sclerosing cholangitis.
Pyoderma gangrenosum has been associated with the administration of drugs including interferon (IFN)- α in the
setting of chronic granulocytic leukemia, the antipsychotic agents sulpiride and colony stimulating factors.
Pyoderma gangrenosum has four distinctive clinical and histopathological variants:
• Bullous pyoderma gangrenosum.
• Ulcerative.
• Pustular.

• Vegetative (vegetative pyoderma gangrenosum).
Histopathology
A biopsy is usually performed in all cases of pyoderma gangrenosum, notably to eliminate other causes of ulceration.
Histopathological findings vary with the age and the site of lesion biopsied.
Earliest Lesions Show
•
•

Follicular and perifollicular inflammation.
Abscess formation in the dermis.

Later Lesions Show
•
•

Necrosis of the epidermis and upper part of dermis resulting in ulcer .
Mixed inflammatory cell infiltrate with abscess formation in the base of the ulcer
subcutis (Fig. 25.1).

, which may even extend to the

Advanced edge of the lesions show
•
•
•

Tight perivascular and intramural infiltrate of lymphocytes and plasma cells with endothelial swelling representing a
lymphocytic vasculitis. There is a controversy regarding the deposit of fibrin in the vessel walls. Necrosis of vessel
walls is usually not seen.
There is often subepidermal edema at the advancing edge.

Bullous lesions of pyoderma gangrenosum show intraepidermal bulla with pustulation and marked subepidermal
edema.


147

Pyoderma Gangrenosum


Fig. 25.1: Pyoderma gangrenosum. Mixed inflammatory cell infiltrate
with abscess formation is seen extending to the subcutis. Necrotic
changes are evident in the epidermis

Areas between edge and ulcer show
Sweet's- like vascular reaction comprising of neutrophils in a loose cuff around the angiocentric lymphocytic infiltrates.
SUPERFICIAL GRANULOMATOUS (VEGETATIVE)
PYODERMA GANGRENOSUM
Superficial granulomatous pyoderma gangrenosum is a chronic and superficial form of pyoderma gangrenosum which
typically occurs on the trunk and forms vegetative or ulcerative lesions with a granulating cleaner base than traditional
pyoderma gangrenosum. The borders of the lesions are not undermined and the condition is not associated with other
underlying diseases.
Histopathology
•
•

Epidermis shows pseudoepitheliomatous hyperplasia.
Three layer inflammatory reaction is seen in the dermis.
The first layer consists of superficial abscess formation in the upper dermis. The second layer demonstrates granuloma
formation with histiocytes and multinucleate giant cells. These granulomas are not caseating or epithelioid as in tuberculosis.
The surrounding third layer is composed of a mixed inflammatory infiltrate with lymphocytes, numerous plasma cells,

neutrophils and eosinophils.
Comparative clinical and histopathological features of vegetative pyoderma gangrenosum (VPG) and pyoderma
gangrenosum (PG).
Table 25.1: Comparison of clinical and histopathological features of VPG and PG

Location
Primary lesions
Number of lesions
Characteristics of lesion
Histopathology
Associated disease

VPG

PG

Most commonly involve the trunk and upper extremities
Nodules or plaques
Solitary or multiple
Superficial, clear base, may be exophytic, slowly
progressive, usually not painful
Three layers: dermal neutrophilic abscess, granuloma,
and mixed inflammatory infiltrate.
Usually no associated disease.

Most commonly invlove the lower extremities
Pustules
Usually solitary
Deep, purplish, undermined border, purulent
base, rapidly enlarges, and painful

Extensive dermal neutrophilic abscess with or
without various degree of vasculitis.
Frequently present.


26

CHAPTER

Urticaria Pigmentosa (UP)
Urticaria pigmentosa is a condition characterized clinically by cutaneous lesions which develop wheal and flare (urticate)
when rubbed or stroked (Darier's sign) and histopathologically by an infiltrate comprising predominantly of mast cells. It
occasionally shows an autosomal dominant mode of transmission.
Four forms of urticaria pigmentosa are recognized:
• Onset in infancy or early childhood without significant systemic lesions and improvement of lesions or even complete
clearing at puberty.
• Onset in adolescence or adult life with occasional systemic lesions which are nonprogressive. Spontaneous regression
of cutaneous lesions does not occur .
• Systemic mast cell disease.
• Mast cell leukemia usually without skin lesions.
In patients with extensive skin or internal organ involvement there are symptoms of flushing, palpitation or diarrhea,
because of degranulation of mast cells and release of histamine.
Five clinical variants of urticaria pigmentosa are recognized:
• Maculopapular type characterized by multiple brown lesions.
• Nodules or plaques.
• Solitary large cutaneous nodule which is seen predominantly in infants.
• Diffuse erythrodermic form.
• Telangiectasia macularis eruptiva perstans which is seen in adults exhibiting faintly pigmented macules on the trunk
and proximal parts of the extremities associated with fine telangiectasia. There is a high incidence of systemic
involvement. The lesions show little or no urtication on stroking.

Special Stains
Giemsa and Leishmans stains are done to highlight the presence of mast cells which show metachromatic granules in
their cytoplasm.
Histopathology
The main histopathologic feature in all clinical variants of urticaria pigmentosa is the presence of an infiltrate composed
chiefly of mast cells, although there may be variations in the number of mast cells present (Fig. 26.1).
Mast cells are characterized by the presence of metachromatic granules in their cytoplasm. These granules are not
appreciated in routine hematoxylin and eosin stain and special stains like Giemsa stain and toluidine blue are employed.
Mast cells are limited to the upper third of the dermis mainly around capillaries in maculopapular type of lesions and
in lesions of telangiectasia macularis eruptiva perstans. Tumor like aggregates of mast cells infiltrating the entire dermis
and even subcutaneous tissue are seen in multiple nodular or plaque lesions and in a solitary large nodule. Mast cells
occurring in dense aggregates tend to possess cuboidal rather than spindle shaped nuclei with ample eosinophilc cytoplasm
dif erythrodermic
and a well-defined border. Dense band like infiltrate of mast cells in the upper dermis is seen in cases of fuse
type of urticaria pigmentosa.


Urticaria Pigmentosa (UP)

Fig. 26.1: Urticaria pigmentosa. Giemsa stain
showing an infiltrate of mast cells

149

Fig. 26.2: Urticaria pigmentosa. Basal cell shows
increased pigmentation which is a clue to the
diagnosis of urticaria pigmentosa

Eosinophils may be present in small numbers in all types of urticaria pigmentosa with the exception of telangiectasia
macularis eruptiva perstans.

• Bullous lesions show subepidermal bulla, however, older bullae may be located intraepidermally,because of regeneration
of the epidermis at the base of the bullae.
• Basal cell layer shows increased pigmentation and melanophages may be seen in the upper dermis. This feature is a
useful clue to the diagnosis of urticaria pigmentosa and is responsible for pigmentation of lesions (Fig. 26.2).


27

CHAPTER

Gyrate and Annular
Erythemas
Gyrate and annular erythemas are characterized clinically by one or more circinate, arcuate or polycyclic erythematous
lesions which may be fixed or migratory (spreading peripherally). These lesions are attributed to hyper-sensitivity to an
agent which may be a drug, infectious agent, food product, neoplasm, arthropod bite or self antigen.
Histopathologically the gyrate and annular erythemas are classified into superficial and deep type (Table 27.1):
Table 27.1: Differentiation between superficial and deep gyrate erythemas
Superficial gyrate erythema

Deep gyrate erythema

Vessels of superficial vascular plexus involved
Slight spongiosis and focal parakeratosis usually seen
Indistinct border
Has trailing scale
More often pruritic

Vessels of both the superficial and deep vascular plexuses involved
No spongiosis or parakeratosis
Firm yet indurated border

Lacks scale
Rarely pruritic

Clinically gyrate and annular erythemas has to be differentiated from:
• Granuloma annulare which usually develops on extensor aspects of the extremities, is non-scaling and non-erythematous.
• Tinea corporis may be scaly, but collarettes of scale are not invariable at the inner margin of the “advancing” border;
instead, vesicles and crust may be seen.
Histopathologically erythema annulare centrifugum is indistinguishable from pityriasis rosea.
ERYTHEMA ANNULARE CENTRIFUGUM
Erythema annulare centrifugum is characterized by presence of one or few annular erythematous lesions that usually has
a tendency to spread peripherally ring-like border of the lesions show collarette of scales on their inner aspect. The lesions
mostly involve the trunk and proximal parts of the limbs and may be pruritic.
Histopathology
In the superficial type the moderately dense infiltrate of lymphocytes, histiocytes and rarely eosinophils is seen around
vessels of superficial vascular plexus (Fig. 27.1). The infiltrate is well demarcated giving a “coat-sleeve” appearance. The
infiltrate may involve the vessel wall but without extravasation of fibrin. Papillary dermis may show slight edema.
Epidermal changes include slight spongiosis and focal parakeratosis.
In the deep type epidermis is unaltered and both superficial and deep vascular plexuses are involved with same type of
infiltrate as seen in superficial variant (Fig. 27.2).