Mesenteric cyst lined with pancreatic heterotopia: Anatomopathological findings in an exceptional case.

Mesenteric cysts are uncommon lesions whose classification is primarily based on their histological origin. We present the case of a mesenteric cyst diagnosed incidentally during staging investigations for colonic adenocarcinoma. Histological examination revealed a multiloculated cystic lesion lined by non-mucinous columnar epithelium without atypia, associated with mature pancreatic acini. Immunohistochemical analysis showed positivity for CK7, CK19, EMA, and trypsin, and negativity for mesothelial, enteric, and lymphatic markers, thereby excluding the subtypes described in current classifications. This exceptional finding, not previously reported, broadens the histopathological spectrum of mesenteric cysts and suggests pancreatic heterotopia as a possible origin of a subtype not recognised to date.