Mucin, Mayhem and Mixed Malignancies: An Appendiceal Saga

Document Type

Conference Proceeding

Publication Date

11-2025

Publication Title

American Journal of Clinical Pathology

Abstract

Introduction/Objective: The appendix is not an uncommon site for primary neoplasms and does occasionally exhibits diverse and complex pathology. We present two unique appendiceal cases. First case with an invasive mucinous adenocarcinoma and goblet cell adenocarcinoma arising in a background of low-grade and high-grade appendiceal mucinous neoplasms (LAMN and HAMN), and case 2 of an appendix and cecum involved by an invasive adenocarcinoma and LAMN. Methods/Case Report: Case 1 presented with a lesion at the appendicular orifice on screening colonoscopy and underwent ileocecectomy. Case 2 presented with a cecal mass extending into the appendix, on computed tomography and hence underwent ileocolectomy. After gross examination, tissue sections from both appendix and colon were submitted and reviewed via hematoxylin and eosin-stained glass slides, and few immunohistochemical stains. Results: The first case demonstrated multiple neoplastic components, including an invasive mucinous adenocarcinoma, goblet cell adeno - carcinoma, LAMN and HAMN (low and high grade appendiceal mucinous neoplasm), within the appendix. The second case revealed a tumor consisting of an invasive adenocarcinoma involving the appendix and cecum in a background of LAMN. Both cases posed significant diagnostic challenges due to the heterogeneity and admixture of the neoplasms. Hence, comprehensive tissue sampling and careful microscopic evaluation are critical for accurate diagnosis and treatment of such complex cases. Conclusion: Due to the limited awareness of appendiceal tumors and associated clinical implications, the above 2 cases underscore the complexity of appendiceal pathology; thereby highlighting the importance of thorough histopathological specimen analysis. The coexistence of multiple neoplastic entities within a single specimen also requires an up to date and heightened knowledge about pathology for appropriate diagnosis and management.

Volume

164

Issue

Suppl 1

First Page

S45

Comments

American Society for Clinical Pathology (ASCP) Annual Meeting, November 17-20, 2025, Atlanta, GA

Last Page

S46

DOI

10.1093/ajcp/aqaf121.109

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