Hepatoid Thymic Carcinoma: A Case Report

ABSTRACT

We report here on a rare case of hepatoid thymic carcinoma in a 34-year-old man. The patient complained of a high fever and headache, and a 6.6cm-sized anterior mediastinal mass was found on chest computed tomography (CT). There was no hepatic mass seen on abdominal CT. The resected mass consisted of epithelioid cells with abundant eosinophilic cytoplasm, pleomorphic vesicular nuclei and prominent nucleoli, and the mass was surrounded by thymic tissue. The tumor cells were immunopositive for cytokeratin 7, alpha-1-antitrypsin, hepatocyte staining, and epithelial membrane antigen, but they were negative for CD5, alpha-fetoprotein (AFP) and placental alkaline phosphatase, and this all led to a diagnosis of hepatoid thymic carcinoma rather than hepatoid yolk sac tumor. This entity should be included in the differential diagnosis of epithelioid thymic tumors.