Mucoepidermoid carcinoma of the liver diagnosed as a liver abscess: report of a case.

Mucoepidermoid carcinoma of the liver is a rare variant of cholangiocarcinoma, containing both mucus-secreting glandular cells and squamous cells mixed in nests. We report a case of mucoepidermoid carcinoma of the liver in a 69-year-old woman who presented with a 1-week history of fever, chills, and right flank pain. On admission, she was not jaundiced, and under a provisional diagnosis of liver abscess, a pigtail catheter was inserted into the abscess cavity. We performed right hepatectomy and partial excision of the diaphragm 1 month later. Microscopically, the tumor was composed of solid and invasive nests of epidermoid and mucin-producing cells with desmoplastic stroma. The epidermoid component of the tumor contained intercellular bridges and individual cell keratinization. Alcian blue and Periodic acid-Schiff (PAS) staining confirmed that there was mucin in the cytoplasm of mucus-secreting cells. The tumor cells, intrahepatic bile ducts, and ductules were consistently reactive with cytokeratin (CK) 7 and negative for CK20. The adjacent nonneoplastic liver cells were CK 7-/CK20-, and P63 immunostaining was positive in the epidermoid cells. The tumor was diagnosed as mucoepidermoid carcinoma arising from the intrahepatic bile duct. Despite aggressive surgical treatment, the patient died of multiple liver metastases 4 months after the right hepatectomy.