Mucocele of the Appendix

Definition

• A gross or clinical descriptive term for dilation of the appendiceal lumen by mucus

Diagnostic Criteria

• Mucocele is a gross or clinical descriptive term
• It is not a pathologic diagnosis
• Dilation of appendiceal lumen by mucus
• Overt obstruction may or may not be demonstrable
• Most cases due to epithelial proliferations (see individual subjects for details)
• Hyperplastic polyp / mucinous hyperplasia
• Sessile serrated adenoma
• Traditional serrated adenoma
• Mucinous adenoma / cystadenoma
• Mucinous neoplasm with low risk of recurrrence
• Mucinous neoplasm with high risk of recurrence
• Mucinous adenocarcinoma
• Inflammatory, post-inflammatory or obstructive causes uncommon
• May be caused by appendicitis, fecalith, endometriosis
• Usually minimal dilation
• Rarely >2 cm
• Mucosa usually markedly thinned or denuded
• No hyperplasia
• No dysplasia
• Acellular mucin may dissect into or through the wall
• The entire appendix should be examined microscopically

Reference

• Pai RK, Longacre TA. Appendiceal mucinous tumors and pseudomyxoma peritonei: histologic features, diagnostic problems, and proposed classification. Adv Anat Pathol. 2005 Nov;12(6):291-311.

Original posting/updates : 10/7/10

Lists

Appendiceal Epithelial Neoplasms and Proliferations

• Adenocarcinoma
• Carcinoid / well differentiated neuroendocrine neoplasm
• Carcinoma ex-goblet cell carcinoid
• Goblet cell carcinoid
• Hyperplastic polyp / mucosal hyperplasia
• Mucinous adenoma / cystadenoma
• Mucinous neoplasm with high risk of recurrence
• Mucinous neoplasm with low risk of recurrrence
• Sessile serrated polyp / adenoma
• Traditional serrated adenoma

Clinical / Descriptive Terms

• Mucocele
• Pseudomyxoma peritonei