A Symptomatic Mucinous Cystic Neoplasm of the Mesentery: A Case Report.

Mucinous cystic neoplasms (MCNs) are rare tumors primarily observed in the pancreas but occasionally found in other locations such as the retroperitoneum, ovary, liver, and spleen. These neoplasms are histologically classified based on the degree of dysplasia, with some associated with invasive carcinoma. Colorectal surgeons infrequently encounter MCNs. Mesenteric MCNs pose a diagnostic challenge secondary to their atypical location, subtle histology, and lack of specific biochemical markers. In this context, we present a case involving a 68-year-old female who initially presented with an assumed ovarian mass. Subsequent exploration revealed a 12 cm MCN situated in the sigmoid mesentery, a location seldom associated with these tumors. The patient underwent laparotomy with successful resection and recovery. Histopathological analysis confirmed the neoplasm's mucinous epithelium with a complex papillary architecture. Immunohistochemical staining supported the diagnosis, revealing positivity for CK7, SATB2, and CDX2.