Incidental Mucocele of the Appendix in a 15-Year-Old Girl

Abstract

Mucocele of the appendix is an exceedingly uncommon pathology in the pediatric population that may present with abdominal pain or represent an incidental finding after routine abdominal imaging. Etiologies may be inflammatory or neoplastic, but all share the commonality of chronic appendiceal obstruction. Early diagnosis is critical for positive long-term outcomes because the operative management will differ from that of a dilated appendix secondary to acute appendicitis.

Appendiceal mucocoele with midgut malrotation

“…1,2,4 These lesions are typically identified in middle aged patients, with no definitive sex predilection. 4 Appendiceal mucocoele is a descriptive term indicating the appendiceal lumen is grossly distended with an abnormal intraluminal accumulation of mucus.…”

“…Pseudomyxoma peritonei is a dreaded complication of mucocoele rupture, resulting in the seeding of mucin secreting epithelial cells into the peritoneal cavity, which causes gelatinous ascites. 4 At present, there only two reported cases in the English literature of presentation with appendiceal mucocoele in adults and malrotation of the midgut. Intestinal malrotation is a congenital anomaly of the midgut.…”

“…1,3,4 Other obstructing lesions such as adenocarcinomas of the colon, carcinoid tumours and endometriosis can also produce mucocoeles. 4 Pathologically, it is believed that mucocoeles exist along a spectrum, beginning with benign appendiceal hyperplasia, leading to adenoma and finally to malignant transformation such as cystadenocarcinoma, similar to the progression of hyperplastic colonic polyps to colon adenocarcinoma. 3,4 The diagnosis can be made radiologically by computed tomography.…”

“…4 Pathologically, it is believed that mucocoeles exist along a spectrum, beginning with benign appendiceal hyperplasia, leading to adenoma and finally to malignant transformation such as cystadenocarcinoma, similar to the progression of hyperplastic colonic polyps to colon adenocarcinoma. 3,4 The diagnosis can be made radiologically by computed tomography. An appendiceal mucocoele appears as a well circumscribed, low attenuation, spherical or tubular mass contiguous to the base of the caecum.…”

“…Most mucocoeles are incidental findings; however, a small portion become symptomatic owing to increasing size, bleeding, infection, torsion or perforation. 3,4 During surgical excision, surgeons must take great care not to spill the abdominal mucocoele's contents as morbidity and mortality from pseudomyxoma are significant. Pseudomyxoma peritonei is a dreaded complication of mucocoele rupture, resulting in the seeding of mucin secreting epithelial cells into the peritoneal cavity, which causes gelatinous ascites.…”