Biliary Mucinous Cystic Neoplasm of the Liver with Ovarian Stroma and Elevated Serum and Cystic Fluid Cancer Antigen 19-9 Levels.

Biliary mucinous cystic neoplasms of the liver are rare cystic tumors comprising less than 5% of the liver cystic neoplasms. These tumors demonstrate a female predominance and entail a risk of malignant transformation. We present a 56-year-old female patient with a multiloculated liver cystic lesion measuring 22 cm who underwent a cystectomy with en bloc resection of the liver segments II, III, and cholecystectomy. Serum cancer antigen 19.9 was 4,122.00 U/ml, supporting the diagnosis of a biliary cystic tumor. The cytology of the cystic fluid was negative for malignancy and intracystic fluid cancer antigen 19.9 level was measured over 12,000.00 U/l. The patient is free of recurrence at one-year follow up. Although a rare entity, the biliary mucinous cystic neoplasms should be considered in the differential diagnosis in the patients with liver cystic tumors. The appropriate management with complete surgical resection with negative margins is recommended given the risk of recurrence and malignant transformation.