pediatric mucinous neoplasm of the appendix presenting as a mucocele a case report and review of the literature

Journal of Pediatric Surgery Case Reports 17 (2017) 11e14

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Journal of Pediatric Surgery Case Reports
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Pediatric mucinous neoplasm of the appendix presenting as a
mucocele: A case report and review of the literature
Barrie S. Rich a, *, Sudarshana Roychoudhury b, Alex K. Williamson b, Richard D. Glick a
a

Division of Pediatric Surgery, Hofstra Northwell School of Medicine, Steven and Alexandra Cohen Children's Medical Center of New York, Northwell Health,
New Hyde Park, NY 11040, USA
b
Department of Pathology, Hofstra Northwell School of Medicine, Steven and Alexandra Cohen Children's Medical Center of New York, Northwell Health,
New Hyde Park, NY 11040, USA

a r t i c l e i n f o

a b s t r a c t

Article history:
Received 27 October 2016
Accepted 27 November 2016
Available online 27 November 2016

Mucocele of the appendix is a rare entity in pediatrics, with few case reports in the literature. We present
a case of a 17-year-old male with right lower quadrant pain who was found to have an appendiceal
mucocele while being evaluated for appendicitis. Laparoscopic-assisted resection was performed, with
pathology confirming a low-grade mucinous neoplasm of the appendix, a tumor scarcely described in the

pediatric population. He underwent complete resection with negative margins, rendering him cured
without the need for any further resection or treatment. We review the literature on this topic.
© 2016 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND
license ( />
Keywords:
Mucocele
Mucinous neoplasm of the appendix
LAMN
Pediatric

1. Introduction
Laparoscopic appendectomy remains one of the most frequently
performed procedures by pediatric surgeons, with acute appendicitis being the most common pathology identified. Unexpected
pathology findings after appendectomy in children are present in
approximately 2% of specimens, and include pinworm, granulomas,
eosinophilic infiltrates and neoplasms [1]. Tumors of the appendix
are rare in the pediatric population, found in less than 0.5% of pathology specimens in this age group, with neuroendocrine tumors
representing the most common tumor-type [1]. Mucoceles due to
appendiceal mucinous neoplasms are exceedingly rare in this
population. We describe a case of a 17-year-old boy with right
lower quadrant pain found to have a mucocele secondary to a
mucinous neoplasm of the appendix, successfully treated by laparoscopic assisted resection.

2. Case report
A 17-year-old boy, with no significant medical history, presented
to the emergency department with one day of abdominal pain. The

* Corresponding author. Division of Pediatric Surgery, 26901 76th Ave, CH158,
New Hyde Park, NY 11040, USA.
E-mail address: (B.S. Rich).

pain was initially diffuse, and subsequently localized to the right
lower quadrant. The pain was described as sharp and constant. It
was associated with emesis, but no fevers, diarrhea, or urinary
symptoms. The remainder of review of systems was within normal
limits. He had no family history of malignancy.
On physical exam, he was well-appearing and afebrile with
normal vital signs. His abdomen was soft and tender in the right
lower quadrant with localized rebound tenderness. His laboratory
values were normal, including a white blood cell count of 7.6 K/mL
with an Auto Neutrophil % of 53.3%. An ultrasound of his abdomen
demonstrated a blind-ending tubular structure measuring upwards
of 2.5 cm. This structure was seen to extend from the cecum, but did
not demonstrate any wall thickening or increased vascularity. The
luminal contents appeared hypoechoic. The impression by the pediatric radiologist was appendicitis versus a mucocele of the appendix (Fig. 1). Given these findings, the patient was taken to the
operating room for laparoscopic appendectomy using a standard
three-port technique. The appendix was easily identified in the
right lower quadrant. It was significantly dilated and tense (Fig. 2a
and b). There was no evidence of any free fluid or any mucinous
deposits throughout the abdomen and pelvis, including the peritoneal surfaces. In order to better examine the appendix and assure
adequate resection, the appendix and cecum were carefully mobilized bluntly from their attachments to the right lower quadrant
and eviscerated out of the umbilical incision using a wound protector/retractor (Fig. 2c).

/>2213-5766/© 2016 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license ( />

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B.S. Rich et al. / Journal of Pediatric Surgery Case Reports 17 (2017) 11e14

Fig. 1. Ultrasound of right lower quadrant showing 2.5 cm appendix with hypoechoic

contents.

The appendix was diffusely firm to the base of the cecum. An
appendectomy with partial cecectomy was performed using a
3.5 mm Endo GIA stapler, taking care to resect the specimen at an
area of normal cecum (Fig. 2d, e, f). There was no violation or
spillage of the appendiceal contents and the intact specimen was
submitted for intraoperative pathologic consultation. The frozen
section diagnosis was a low-grade appendiceal mucinous neoplasm
(LAMN), and after a multidisciplinary intraoperative discussion, the
decision was made to conclude the procedure with appendectomy
only.
The patient did well post-operatively and was discharged home
on post-operative day 2. Gross pathologic examination revealed a
dilated, intact appendix measuring 10 Â 3.5 Â 1.0 cm and cecum
measuring 3.5 Â 1.5 Â 0.5 cm (Fig. 3a). The appendix mucosa was
flat and the lumen was filled with tenacious mucin. Microscopic
pathologic examination revealed a low-grade appendiceal
mucinous neoplasm (LAMN), consisting of flat to villiform
mucinous epithelium with basal nuclei and abundant apical cytoplasmic mucin, without nuclear atypia, evidence of invasion, or

Fig. 2. a. Laparoscopic visualization of mucocele in right lower quadrant, b. laparoscopic mobilization of appendix and cecum c. extracorporealization of appendix and cecum
through umbilical port site using wound protector d. stapled resection of appendix and partial cecectomy e. Resected specimen grossly intact f. Staple line.


B.S. Rich et al. / Journal of Pediatric Surgery Case Reports 17 (2017) 11e14

13

The patient and his family had significant anxiety after learning

of this rare and surprising diagnosis. This was associated with
intermittent self-limited vague abdominal pain for several months
resulting in a CT scan at 5 months postoperatively. This study
showed no abnormality. He is now 6 months postoperative and
doing well.
3. Discussion

Fig. 3. a. Gross image of fixed and opened specimen showing smooth, tan appendiceal
lumen and brown cecal orifice at left b. Low-power histologic image of appendix
showing flat to villiform mucosa with mucinous epithelium c. High-power histologic
image of appendix showing epithelium with apical mucin, basal nuclei, and confinement to the mucosa, as well as fibrosis and inflammation in the lamina propria.

extra-appendiceal mucin. The lamina propria showed some fibrosis
and patchy chronic inflammation, and the distal appendiceal tip
was obliterated by benign spindle cell mesenchymal tissue. The
cecal margins and one mesenteric lymph node were negative for
neoplasm (Fig. 3b and c).

Mucocele of the appendix is a general term referring to a cystically dilated appendix filled with mucin secondary to non-acute
appendiceal obstruction. The obstruction can be secondary to an
appendicolith, endometriosis, extrinsic compression, inflammation, or neoplasm, and therefore surgical resection and pathologic
evaluation are recommended. Mucoceles are rarely reported in
children, with limited case reports documented. Two recent case
reports describe children with appendiceal mucoceles that were
each resected without any underlying neoplasm, one from a 15 year
old girl found to have a thickened appendiceal base during laparoscopic appendectomy without any other pathology, and the other
from an 11-year old boy with phlegmono-gangrenous appendicitis
causing obstruction and subsequent mucocele [2,3].
Mucinous neoplasms of the appendix are a heterogeneous
collection of appendiceal epithelial neoplasms that can obstruct the

lumen of the appendix while secreting excess mucin, and are
thought to cause appendiceal mucocele. They are rare lesions,
found in approximately 0.2e0.7% of pathology specimens following
appendectomy [4,5]. They can present mimicking acute appendicitis with right lower quadrant pain, as an abdominal mass, with an
intussusception, or incidentally. They are often diagnosed during a
work-up for abdominal pain by ultrasound or cross sectional imaging of the abdomen and pelvis for other indications.
Appendiceal mucinous neoplasms are seldom seen in the pediatric population, as they typically present in the sixth decade of
life [6,7]. Alemayehu et al. reported the incidence of unexpected
pathology findings after appendectomy in 3602 children over a 16year period, and none were found to have a mucinous neoplasm [1].
Pai et al. described 116 cases of appendiceal mucinous neoplasms
over approximately 30 years, and only two patients were under 20
years of age [7]. Blecha et al. reported a case of a ten-year old boy
found to have a mucocele of the appendix with a cystadenoma.
Similarly to our patient, he presented with right lower quadrant
pain. Unlike our patient, who was diagnosed by ultrasound, the
reported child was diagnosed by computed tomographic (CT) scan,
and he also underwent surgical resection with appendectomy and
partial cecectomy with a 1 cm margin of cecum [8].
Appendiceal mucinous tumors represent a continuum ranging
from benign to malignant neoplasms, with numerous proposed
classification schemes and subtypes. The WHO classification designates three groupings of mucinous neoplasms including
mucinous adenoma, LAMN, and appendiceal adenocarcinoma [9].
This categorization was corroborated in a recent international
consensus for classification of appendiceal neoplasia, with the
addition of high-grade appendiceal mucinous neoplasia [10]. Misdarji and colleagues first described LAMN in 2003 in an effort to
clarify an intermediate group of tumors [11]. They are typically
defined as lesions confined to the appendix or the local periappendiceal tissues without evidence of invasion or disseminated
peritoneal disease. They are further subclassified based on the degree of extra-appendiceal spread. The best prognosis is seen with
LAMN confined to the appendix without any evidence of extraappendiceal mucin. In one report of localized type, there were no
recurrences in 27 patients after resection with a median follow up

of six years [11]. Similarly, Pai et al. describes 16 patients with
LAMN confined to the appendix without any post-operative


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B.S. Rich et al. / Journal of Pediatric Surgery Case Reports 17 (2017) 11e14

recurrences with a mean follow up of 5.25 years [7]. Mucin is
divided into cellular and acellular depending on whether it contains or lacks neoplastic cells, respectively. LAMN with acellular
mucin in the right lower quadrant manifests a low risk of recurrence or progression to pseudomyxoma peritonei (PMP), approximately 4e8% [7,12], whereas LAMN with cellular mucin in the right
lower quadrant demonstrates a higher risk of recurring as
disseminated disease, as high as 33e75% [7,11].
Surgical resection is the mainstay of treatment for LAMN. When
LAMN is confined to the appendix, complete resection by appendectomy with a negative proximal margin is sufficient for cure. If a
large base of the appendix is found, a cecal resection may be
necessary to assure a negative margin for the appendiceal stump. If
neoplastic epithelium involves the proximal resection margin,
some authors recommend further resection with cecectomy [7]. In
contradistinction, Arnason et al. report that LAMN confined to the
appendix with involvement of the appendectomy margin by either
neoplastic epithelium or acellular mucin does not predict recurrence of disease without further resection. Furthermore, there was
no evidence of neoplasia in any of the re-resected specimens. These
authors recommend a more conservative approach with colonoscopy and radiographic studies for surveillance in the setting of a
positive margin [13]. In cases with extra-appendiceal spread,
complete resection of the appendix is necessary along with resection of any grossly involved surrounding periappendiceal tissue or
implants. Cytologic examination of any mucin or ascites in the
peritoneal cavity is obligatory. Right hemicolectomy is only indicated for invasive adenocarcinomas without peritoneal disease
[14]. Cytoreductive surgery with intraperitoneal chemotherapy is
recommended for disseminated peritoneal disease [15,16].

The use of laparoscopy for LAMN has been reported to be both
safe and feasible provided the appendix is cautiously handled and
dissected without violation or rupture and subsequent dispersion
of mucin [17,18]. This is critical as rupture of these tumors can lead
to peritoneal seeding of mucin-producing epithelial cells, or PMP,
and portends a poorer prognosis [7]. Misdrahi et al. affirms this
increase in mortality with a 45% 10-year survival rate of patients
with LAMN with extra-appendiceal spread [11]. Laparoscopy also
allows for careful and complete examination of the peritoneal
surfaces of the abdomen and pelvis to rule out dissemination. Our
patient successfully underwent laparoscopic dissection with
extracorporeal resection through a limited umbilical incision with a
wound protector/retractor. This technique utilized careful laparoscopic tissue handling without rupture or gross spillage of the appendix, while simultaneously allowing for tactile assistance to
assure negative gross margins. This was completed without the
need for an enlarged incision or any subsequent surgical resection.
Pathologic examination of our patient's specimen verified a LAMN
confined to the mucosa and a negative cecal margin, corroborating
complete resection and cure.
There is no standard recommendation for surveillance of LAMN
after resection, especially in a pediatric patient who would necessitate long-term observation. In patients subclassified as low-risk
LAMN, McDonald et al. recommended a watch-and-wait policy
with surveillance imaging at 6 months, then annually. The authors
promote long-term surveillance and follow-up with a specialist
service [19]. For ruptured neoplasms, Murphy et al. recommends
baseline tumor markers and a CT scans every year for 5 years, then
every 2 years for 10 years to monitor for any long term recurrence
[20]. Our patient has already had cross-sectional imaging at 5

months post-operatively.
4. Conclusion

Appendiceal mucinous neoplasms are rare tumors in the pediatric population but should be considered when a mucocele is
identified pre-operatively or intra-operatively. LAMN is a lowgrade neoplasm treated by complete surgical resection when
confined to the appendix. A laparoscopic-assisted approach with
careful handling to prevent rupture is advocated, and an extracorporeal resection may assist in assuring negative margins and subsequent cure. Further studies are needed to assess the long-term
surveillance and follow-up necessary for pediatric patients with
LAMN.
References
[1] Alemayehu H, Snyder CL, St Peter SD, Ostlie DJ. Incidence and outcomes of
unexpected pathology findings after appendectomy. J Pediatr Surg 2014;49:
1390e3.
[2] Arrington D, Jewett B, Sterner S, Caplan M, Thacker P. Incidental mucocele of
the appendix in a 15-year-old girl. Pediatr Emerg Care 2014;30(8):555e7.
[3] Balint IB, Nad M, Kiraly A, Bali O, Rashed A, Vizsy L. Giant appendix or an
appendiceal mucocele? Case report of an 11-year-old child. Interv Med Appl
Sci 2014;6(4):187e90.
[4] Marudanayagam R, Williams GT, Rees BI. Review of pathological results of
2660 appendicectomy specimens. J Gastroenterol 2006;41(8):745e9.
[5] Smeenk RM, van Velthuysen MLF, Verwaal VJ, Zoetmulder FA. Appendiceal
neoplasms and pseudomyxoma peritonei: a population based study. Eur J
Surg Oncol 2008;34(2):196e201.
[6] Aho AJ, Heinonen R, Lauren P. Benign and malignant mucocele of the appendix. Histological types and prognosis. Acta Chir Scand 1973;139(4):
392e400.
[7] Pai RK, Beck AH, Norton JA, Longacre TA. Appendiceal mucinous neoplasms
clinicopathologic study of 116 cases with analysis of factors predicting
recurrence. Am J Surg Pathol 2009;33(10):1425e39.
[8] Blecha MJ, Gupta A, Hoover JD, Madonna MB. Chronic abdominal pain secondary to a mucous cystadenoma of the appendix in a 10-year-old boy.
J Pediatr Surg 2005;40:1792e4.
[9] Carr N, Sobin L. Tumors of the appendix. In: Bosman FT, Carneiro F,
Hruban RH, Theise ND, editors. WHO Classification of tumours of the digestive
system. World Health Organization classification of tumours. fourth ed.vol. 3.

Lyon, France: IARC Press; 2010. p. 122e5.
[10] Carr NJ, Cecil TD, Mohamed F, Sobin LH, Sugarbaker PH, Gonzalez-Moreno S,
et al. A consensus for classification and pathologic reporting of pseudomyxoma peritonei and associated appendiceal neoplasia. The results of the peritoneal surface oncology group international modified delphi process. Am J
Surg Pathol 2016;40(1):14e26.
[11] Misdraji J, Yantiss RK, Grame-Cook FM, Balis UJ, Young RH. Appendiceal
mucinous neoplasms: a clinicopathologic analysis of 107 cases. Am J Surg
Pathol 2003;27(8):1089e103.
[12] Yantiss RK, Shia J, Klimstra DS, Hahn HP, Odze RD, Misdraji J. Prognostic
significance of localized extra-appendiceal mucin deposition in appendiceal
mucinous neoplasms. Am J Surg Pathol 2009;33:248e55.
[13] Arnason T, Kamionek M, Yang M, Yantiss RK, Misdraji J. Significance of
proximal margin involvement in low-grade appendiceal mucinous neoplasms. Arch Pathol Lab Med 2015;139:518e21.
[14] Gonzalez-Moreno S, Sugarbaker PH. Right hemicolectomy does not confer a
survival advantage in patients with mucinous carcinoma of the appendix and
peritoneal seeding. Br J Surg 2004;91:304e11.
[15] Sugarbaker PH, Chang D. Results of treatment of 385 patients with peritoneal
surface spread of appendiceal malignancy. Ann Surg Oncol 1999;6:727e31.
[16] Sugarbaker PH. New standard of care for appendiceal epithelial neoplasms
and pseudomyxoma peritonei syndrome? Lancet Oncol 2006;7:69e76.
[17] Lau H, Yuen WK, Loong F, Lee F. Laparoscopic resection of appendiceal
mucocele. Surg Laparosc Endosc Percutaneous Tech 2002;12(5):367e70.
[18] Miraliakbari R, Chapman III WHH. Laparoscopic treatment of an appendiceal
mucocele. JLAST 1999;9(2):159e63.
[19] McDonald JR, O'Dwyer ST, Rout S, Chakrabarty B, Sikand K, Fulford PE, et al.
Classification of and cytoreductive surgery for low-grade appendiceal neoplasms. Br J Surg 2012;99:987e92.
[20] Murphy EMA, Farquharson SM, Moran BJ. Management of an unexpected
appendiceal neoplasm. Br J Surg 2006;93:783e92.