Mucoepidermoid carcinoma of the liver.

Pianzola, Luis E., and Drut, Ricardo: Mucoepidermoid carcinoma of the liver. Amer. J. Clin. Path. 56: 758-761, 1971. This first case of mucoepidermoid carcinoma of the liver to be reported was discovered in a 44-year-old man with an 8-month history of fever, vomiting, weight loss (15 kg.), and pain in the right hypochondrium. A right hemihepatectomy disclosed a 15 cm. tumor located above the gallbladder bed. Histologically, the growth was composed of nests of epidermoid and mucus secreting cells, sometimes with cystic spaces in the center of the nests. Intercellular bridges and keratinization were present in the epidermoid parts of the tumor. The mucus-secreting cells were periodic acid-Schiff and Alcian blue positive. Necropsy revealed no remaining tumor or metastases in other organs. It is suggested that epidermoid elements may arise from the biliary ducts as they do from salivary ducts. MALIGNANT EPITHELIAL TUMORS of the liver can be grouped as follows: (1) hepatic cell carcinoma or hepatocarcinoma; (2) carcinoma of the bile ducts or cholangiocarcinoma; (3) cholangiolohepatoma; and (4) hepatoblastoma or teratoid tumor of the liver in its two varieties: (a) the epithelial type or epithelial hepatoblastoma, and (b) the epithelial and mesenchymatous type or mixed hepatoblastoma. Routine findings in the latter are strands of more or less keratinized squamous cell elements with or without pearls, a histopathologic feature of these tumors. In 1898, Misick was the first to comment on squamous cell foci in a hepatic tumor, describing "cholesteatomalike" bullae or pearls, which he considered to be of endodermal origin. Even though tire ectoderm does not form part of the liver, Ishak and Glunz believe that an ectodermal origin cannot be discarded, since tridermal teratomas in the liver have been described. In cases reported since then, authors have confined their comments to descriptions of the epidermoid elements, without explaining how they came to be there. In Received January 21, 1971; accepted Cor publication February 23, 1971. 1958, Edmondson first described a case of epidermoid carcinoma of the liver, apparently arising in an epidermal cyst located within the liver. While studying the ultrastructure of hepatoblastomas, Ito and Johnson discovered cells with intracytoplasmic fibrils, 70 A in diameter, distributed in bundles near the nucleus, in one of their cases. The authors suggest they represent incomplete keratinization in a metaplastic process, considering that their size is similar to that of the tonofibrils. Ruebner and co-workers found intracytoplasmic fibrils in the canalicular cells of a cholangiocarcinoma. These findings lead us to admit the occasional presence of epidermoid epithelial components in mixed as well as in simple hepatic tumors, an assumption supported by our own finding of a hitherto undescribed mucoepidermoid tumor of the liver.