Unexpected pathological lesions of appendix: an analysis of 3000 surgical specimens from Sri Lanka

Background: Unexpected pathological lesions are not infrequent findings in surgical specimens of appendix. Appendiceal malignancies are commonly encountered as incidental lesions.

Objective: To analyze the unexpected appendiceal pathological lesions encountered in surgical specimens in a sample of Sri Lankan patients.

Methods: A retrospective review of 3000 consecutive appendicectomy specimens and appendices in colectomy specimens received at the Department of Pathology, Faculty of Medicine, University of Peradeniya from 2001 to 2014.

Results: There were 2907 appendicectomy specimens and 93 colectomy specimens with an appendix. In appendicectomy specimens, there were 9 (0.3%) primary neoplasms of which 8 were malignant, 2 (0.06%) secondary carcinoma deposits, 7 (0.24%) endometriosis, 7 (0.24%) granulomatous inflammation, 2010 (69.1%) acute appendicitis and the rest (30%) were unremarkable. In the appendices of colectomy specimens, there were 4 (4.3%) primary neoplasms, all of which were malignant, 7 (7.5%) secondary carcinoma deposits, 1 (1.1%) granulomatous inflammation, 11 (11.8%) acute appendicitis and the rest (75.2%) were unremarkable. Of the 3000 specimens, 13 (0.4%) had a primary appendiceal neoplasm: 9 (0.3%) mucinous neoplasms, 3 (0.1%) NET G1 (carcinoids) and 1 (0.03%) sessile serrated adenoma. Of the mucinous neoplasms, 1 was an adenoma, 3 were low grade appendiceal mucinous neoplasms and 5 were adenocarcinomas. Caseous tuberculoid granulomata were present in 5/8 (62.5%) granulomatous appendicitis.

Conclusions: The commonest unexpected finding in the appendicectomy sample was primary malignant tumours (0.3%) and the commonest malignant tumour group was mucinous neoplasms. Secondary adenocarcinoma is the commonest pathology in the appendices of colectomy specimens. Most granulomatous appendicitis cases were suggestive of tuberculosis.