Desmoid Mimicking Cystic Pancreatic Lesion: A Case Report

Desmoid tumors, also called deep or aggressive fibromatosis, are uncommon mesenchymal tumors characterized by proliferation of fibroblasts in an abundant collagen extracellular matrix. They rarely involve the pancreas, and the diagnosis is difficult to make if they do. Only eleven cases have previously been reported involving the pancreas in a review of the literature. In these reported cases, seven patients had solid tumors, three patients had solid tumors with intratumoral cystic components, and only one patient had a cystic tumor. However, the only patient who had a pure cystic tumor was affected with familial adenomatous polyposis (FAP). We herein report an extremely rare case of a sporadic desmoid tumor involving the pancreatic tail, presenting as a cystic lesion. To our knowledge, this is the first reported case of a ＂sporadic＂ desmoid tumor involving the pancreas, presenting as a pure cystic lesion.