Fine needle aspiration biopsy of hepatic leiomyosarcoma. An unusual epithelioid variant posing a potential diagnostic pitfall in a hepatocellular carcinoma-prevalent population.

OBJECTIVE: To study the cytomorphologic features of hepatic smooth muscle tumors on fine needle aspiration biopsy (FNAB) material in a hepatocellular carcinoma (HCC)-prevalent population, in which a potential diagnostic pitfall is an unusual variant of metastatic epithelioid leiomyosarcoma seen on aspiration cytology.

STUDY DESIGN: FNABs of five cases of metastatic hepatic leiomyosarcomas were studied cytohistologically and immunocytochemically. In addition, ultrastructural studies were performed in one unusual case. Resected hepatic specimens and all other relevant histopathologic specimens were reviewed.

RESULTS: Classically, aspirates of leiomyosarcoma produced syncytial masses of spindle cells characterized by overlapping, cigar-shaped nuclei and truncated ends. An unusual variant of metastatic epitheliod leiomyosarcoma was studied, with cytohistologic, immunohistochemical and ultrastructural correlation.

CONCLUSION: Hepatic spindle cell lesions consist mainly of metastatic leiomyosarcomas. The diagnosis of malignancy and metastatic status of hepatic smooth muscle tumors is facilitated by the presence of an extrahepatic primary tumor. In a hepatitis B virus-endemic population, HCC, sarcomatoid type, has to be considered in the differential diagnosis of hepatic spindle cell lesions and the classic type, in epithelioid variants of smooth muscle tumors.