Mucinous cystic neoplasm of liver masquerading as hydatid cyst: An error needs to be avoided.

Introduction Mucinous cystic neoplasms (MCNs) are uncommon non-invasive lesion of the liver. The diagnosis of such lesions relies heavily on the histopathological findings. They are often misinterpreted as hydatid cysts clinically and on imaging leading to impartial resection. Methods A 32-year-female presented with pain in upper abdomen and a well-defined cystic lesion with thin septae in segment III/IV of liver. Robotic deroofing of cyst was performed. Microscopy confirmed the diagnosis of mucinous cystadenoma. In view of histopathology and raised fluid carcinoembryonic antigen and CA19-9, she was re-operated for complete excision of cystadenoma. Subsequent, histopathology reported mucinous cystadenoma with clear margins. In another case, a 57-year-female presented with awareness of lump in right hypochondrium. A large unilocular cystic mass lesion noted in the segment IVb/V of liver. Intraoperatively, ~1 liter of cyst fluid was drained with de-roofing done. Her histopathology was suggestive of MCN of the liver with no features of malignancy. She was contacted but lost to follow-up. However, after 2 years she reported with complaints of pain in upper abdomen. Contrast enhanced computed tomography of abdomen revealed a persistent multilocuated cystic lesion in the remaining segment IVb of the liver. Re-resection of residual lesion was performed and histopathology confirmed MCN. Results Both the patients are doing well after 1 year of re-do surgery and having no features of recurrence. Conclusions MCNs of liver are rare with wide clinical & radiological presentation and may be misdiagnosed pre-operatively as hydatid cyst especially in endemic zones. Complete excision, even if re-do surgery is required, prevents future recurrence and malignant conversion.