Radiologic and Pathologic Findings of a Huge Solitary Fibrous Tumor of the Liver with Malignant Transformation: A Case Report

Solitary fibrous tumors (SFTs) are mesenchymal tumors that mostly occur in the pleural cavity. Extra-thoracic location is rare and hepatic origin is extremely rare. Most lesions are benign, 10% - 15% show aggressive behavior and few metastasizing SFTs have been reported. Imaging features of solitary fibrous tumors of the liver (SFTLs) are nonspecific and definite diagnosis usually needs histopathological and immunohistochemistry evaluation. We report ultrasound, CT and MRI features of such a rare malignant SFTL in a 47-year-old man who came with vague abdominal symptoms in detail along with reviewing literature considering imaging features which is valuable for radiologists. The lesion seen as a huge dominantly cystic lesion on ultrasound was initially misinterpreted as hydatid. On CT scan it was seen as a large encapsulated mass with arterial hyper-enhancement and delayed contrast retention and multiple cystic spaces. On MRI, solid components showed iso-intensity to adjacent liver on T1 and T2 images, small areas of restriction on diffusion weighted imaging (DWI) and few hemorrhagic cystic components beside enhancement pattern and multiple large cystic components similar to CT scan. Our patient was admitted for resection of huge hepatic mass and experienced an episode of altered mental status due to hypoglycemia during hospital admission, which is a rare finding in SFTL. The patient underwent right hepatectomy and solitary fibrous tumor was confirmed on pathologic examination of the resected tumor. Hypoglycemic episodes were resolved and the patient was asymptomatic in 28 months follow-up.