Squamous cell carcinoma of the pancreas with massive invasion of the retroperitoneum.

A 79-year-old woman with a rare form of pancreatic carcinoma with massive invasion of the retroperitoneum presented with upper abdominal pain and vomiting. Although examination (computed tomography, barium enema, upper gastrointestinal series) suggested peritonitis carcinomatosa due to pancreatic cancer, a primary lesion of the pancreas was not confirmed by endoscopic retrograde pancreatography. Autopsy ultimately revealed a small tumor (5 x 8 mm) of the uncinate process of the pancreas near the duodenum with peritonitis carcinomatosa. Microscopically, the tumor and its metastasis consisted of poorly differentiated squamous cell carcinoma without adenocarcinomatous change, a rare form of pancreatic tumor.