Colloid Carcinoma of the Pancreas: A Rare Initial Presentation of Lynch Syndrome.

Patients with Lynch syndrome, most commonly associated with colorectal cancer, have an increased risk of developing other tumors including pancreatic ductal adenocarcinoma and precursor lesions, such as intraductal papillary mucinous neoplasms. Here, we present a case of a man in his early 20s who presented with a retroperitoneal mass involving the head of the pancreas. Following a pancreaticoduodenectomy combined with para-aortic lymphadenectomy, a pathologic diagnosis of colloid carcinoma, also known as mucinous noncystic carcinoma, of the pancreas was reported. Further testing established the diagnosis of Lynch syndrome. This case is unique because colloid carcinoma of the pancreas is rare and has never been reported as an initial presentation of Lynch syndrome.