Endometrial adenocarcinoma without myometrial invasion metastasizing to the pancreas and masquerading as primary pancreatic neoplasm

Reported herein is a case of endometrial adenocarcinoma without myometrial invasion that metastasized to the pancreas in a 69-year-old Japanese woman who had a history of hysterectomy. Although systemic radiography could not detect any metastasis in the whole body before hysterectomy, imaging performed 2 months after the hysterectomy consisting of CT, magnetic resonance imaging, gallium scintigraphy and positron emission tomography identified a solitary pancreatic tumor. Imaging demonstrated an intracystic papillary growth in the pancreas, suggesting intraductal papillary mucinous neoplasm or mucinous cystic neoplasm. Excised in distal pancreatectomy, the tumor was diagnosed as a pancreatic primary, an invasive papillary adenocarcinoma at first, but both the endometrial tumor and the pancreatic tumor demonstrated similar morphology and immunohistochemistry. Furthermore, the identical nucleotide mutation of TP53 gene was observed from both the endometrial and pancreatic tumors. The pancreatic tumor was therefore confirmed to be a metastasis from the primary endometrial adenocarcinoma. Metastasis to the pancreas from endometrial carcinoma is extremely rare but must be considered even if the previous cancer was treated at an early stage. Histopathological comparison study and genetic analysis are important for the correct diagnosis of metastasis.