A desmoid-type fibromatosis in the retroperitoneum of the gastro-pancreatic region that was resected with a distal pancreatomy: a case report oleh Toru Imagami, MD, Takeshi Togawa, MD, Yasumitsu Oe, MD, Akiyoshi Mizumoto, MD, Michiko Hino, MD, Shizuki Takemura, MD