Mucoepidermoid carcinoma arising from a preexisting cyst of the liver.

A case of mucoepidermoid carcinoma of the liver of a 46-year-old female is described. The resected mass from the left lobe of the liver measured 3 X 3 X 2 cm. The cut surface showed a well demarcated white, round shape, and a cystic formation measuring 1.8 X 1.4 cm was present in the center of the mass. Microscopically, the mass showed high-grade-type mucoepidermoid carcinoma, which consisted of squamous cells, mucus-producing cells, and glandular cells. The cystic wall was lined with apparently benign glandular, mucus-producing cells, squamous metaplastic cells, and tumor cells. The tumor was intimately contiguous with the cyst and gradual transition between tumor cells and cystic lining cells was recognized. It is suggested that the mucoepidermoid carcinoma of the liver in the present case was derived from malignant transformation of a preexisting cyst of the liver.