Histopathologic study of Mucinous lesions of the appendix

Abstract

Mucinous lesions of appendix are rare with an incidence of about 0.2 to 0.7% of all the appendicetomy specimens. The mucinous lesions of appendix range from simple retention cyst to malignant mucinous adenocarcinoma. Majority of mucinous appendiceal neoplasia are epithelial type (70%) with circumferential involvement of mucosa. Peritoneal seeding and pseudomyxoma peritonei can occur with both frankly malignant as well as low-grade appendiceal neoplasms. Nearly 50% of appendiceal malignancies present clinically as acute appendicitis and can be detected by imaging modalities. Aim of this study is to analyse the incidence, age and sex prediliction, clinical presentation and histopathology of mucinous lesions of appendix. It is a reterospective study of all the mucinous lesions of appendix diagnosed at Dept. of Pathology, Kamineni Academy of Medical Sciences and Reserch Centre (KAMSRC) from 2013-2017. Clinical details and relevant radiological investigations are noted from case sheets. Microscopic examination is done on slides stained with routine H & E and AB-PAS. Diagnosis and classification is based on WHO 2010 and recommendations in the AJCC 8th edition. Mucinous lesions accounted for 0.8% (10/1200). of all appendicetomy specimens. The study included 10 cases of mucinous lesions of appendix(10 cases): Simple mucocele (2 cases), Benign mucinous adenomas(3 cases), Low grade Appendiceal Mucinous Neoplasm (LAMN) with pseudomyxoma peritoni (PMP) (1 case), Mucinous cystadeno carcinomas (4 cases). Benign lesions are seen in females and at a younger age as compared to malignancies which are common in males and at a older age. Most common presentation is abdominal pain followed by appendicitis. Mucosal hyperplasia and high grade appendiceal mucinous neoplasms(HAMN) are not seen in our study. Mucinous lesions of appendix are rare. They are more common in females and associated with non-specific clinical features. Histopathology is critical for establishing diagnosis, further management and prognostication of all the mucinous lesions of appendix.