A case of indeterminate mucin-producing cystic neoplasm of the pancreas presenting with acute rupture

Abstract

A 76-year-old male was transported to the hospital by ambulance for abdominal pain that occurred during exercise at a sports gym. Contrast-enhanced CT revealed a round tumor-like lesion in the pancreatic tail. Extravasation and surrounding ascites were observed. Emergency distal pancreatectomy with splenectomy was performed. The resected specimen was a cystic neoplasm of the pancreas with fibrous membrane, and the cyst was lined by columnar epithelium with atypia. Although similar to mucinous cystic neoplasm (MCN), no clear ovarian-like stroma was observed. Three months after surgery, local recurrence developed in the transverse mesocolon and thus, repeat resection was performed. The specimen from the repeat resection was also a cystic tumor, and invasion into the transverse mesocolon was observed. Although the tumor contained the ovarian-like stroma observed in MCN, the stromal cells were negative for estrogen and progesterone receptors. Consequently, MCN could not be determined and a diagnosis of indeterminate mucin-producing cystic neoplasm of the pancreas was made.