Pseudosarcomatous cystadenocarcinoma of the liver

A case of papillary cystadenocarcinoma with spindle (pseudosarcomatous) metaplasia of the liver is described in a 64-year-old woman. This tumor was solitary, multiloculated, and had a fibrous pseudocapsule. It was composed of undifferentiated malignant epithelial cells, which lined cystic spaces, with sarcomatous cells underneath. Immunohistochemical studies showed no detectable alpha-fetoprotein in the tumor; keratin was present in epithelial and spindle tumor cells, and alpha 1-antitrypsin was present in cytoplasm of many tumor cells. Intracytoplasmic periodic acid--Schiff-positive, diastase-resistant globules, some of them reactive for alpha 1-antitrypsin, were seen. A primary liver tumor with this histology has not been described previously in the literature.