Background : Mucinous cystic neoplasms (MCN) or mucinous cystic pancreatic neoplasms (MCPN) are mucin-producing cystic lesions, typically found at the pancreatic body and tail. The precise etiology is still unknown, but female reproductive hormones have been thought to play crucial roles. Hence, they occur almost exclusively in middle-aged females. Although they are often benign, they have the potential risk of malignancy.

Methods : To our knowledge, this is the first case report of a rare MCPN in Indonesia.

Results : Here, we present a case report of a 50-year-old Indonesian female at Hasan Sadikin Hospital, Bandung, Indonesia. The patient complained of abdominal pain six months ago, which was accompanied by enlargement of the abdomen and fullness sensation. Physical examination revealed a palpable, non-pulsating mass in the epigastric region, extending to the suprapubic region. A CT scan of the abdomen revealed a cystic mass in the retroperitoneal, extending from the body and tail of the pancreas and measuring approximately 25cm in diameter. The patient underwent exploratory laparotomy and distal pancreatectomy. Intraoperative findings include a 25x20x10 cm cystic mass at the body and tail of the pancreas. No post-operative complication was encountered, and the patient was discharged ten days post-operative.

Conclusions : Despite having benign characteristics, MCPNs carry a risk of malignancy. Therefore, appropriate evaluation, monitoring, and treatment should be done in suspicion of MCPNs.