Journal of Pediatric Surgery Case Reports 17 (2017) 11e14 Contents lists available at ScienceDirect Journal of Pediatric Surgery Case Reports journal homepage: www.jpscasereports.com 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 (http://creativecommons.org/licenses/by-nc-nd/4.0/) Keywords: Mucocele Mucinous neoplasm of the appendix LAMN Pediatric 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 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: brich@northwell.edu (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) http://dx.doi.org/10.1016/j.epsc.2016.11.014 2213-5766/© 2016 The Authors Published by Elsevier Inc This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) 12 B.S Rich et al / Journal of Pediatric Surgery Case Reports 17 (2017) 11e14 Fig 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 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 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 months postoperatively This study showed no abnormality He is now months postoperative and doing well Discussion Fig 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 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 14 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 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 years, then every years for 10 years to monitor for any long term recurrence [20] Our patient has already had cross-sectional imaging at months post-operatively 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 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 ... epithelium with basal nuclei and abundant apical cytoplasmic mucin, without nuclear atypia, evidence of invasion, or Fig a Laparoscopic visualization of mucocele in right lower quadrant, b laparoscopic... 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... 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