Primary hepatic solitary fibrous tumor with histologically benign and malignant areas

Extrapleural solitary fibrous tumor (SFT) is an uncommon mesenchymal neoplasm, presenting most commonly in the intrathoracic sites but which has been reported at numerous extrathoracic locations. The majority of intra-thoracic SFTs are benign, but 10%-15% behave aggressively. We report a case of primary hepatic SFT with histologically benign and malignant areas. A 65-year-old man underwent an abdominal CT scan following a cerebrovascular accident, which demonstrated a sharply demarcated large liver mass with a heterogenous enhancing area and occupying most of the left lobe of the liver. Histological examination following a hemihepatectomy showed an SFT with morphological patterns ranging from benign to malignant areas, including pleomorphism, increased cellularity, herringbone pattern, necrosis and a raised mitotic count. On review of the literature, only an occasional case report with malignant areas in a hepatic SFT was identified. This case highlights that SFT should be included in the differential diagnosis of a hepatic spindle cell lesion, and that on rare occasions, malignant areas can occur in this already uncommon neoplasm.