Rapid Interval Growth of a Presumed Simple Hepatic Cyst Revealing a Mucinous Cystic Neoplasm in a Rare Male Presentation.

Hepatic mucinous cystic neoplasms are rare biliary cystic tumors with malignant potential and are particularly uncommon in men. We report a case of a long-standing presumed simple hepatic cyst that demonstrated rapid interval growth and development of complex features, ultimately diagnosed as mucinous cystic neoplasms. Magnetic resonance imaging (MRI) revealed multiloculation, capsular septations, and mild septal enhancement. Histopathology showed mucinous epithelium and specialized mesenchymal stroma supported by immunohistochemistry. Surgical marsupialization was performed due to extensive adhesions from previous cholecystectomy. This case highlights the importance of reevaluating hepatic cysts that enlarge or develop complex features, as timely MRI characterization and surgical assessment are essential.