Histologically Unclassifiable Hepatic Sarcoma: A Case Report

A 55-year-old woman was admitted to our hospital with abdominal distension. CT and MRI showed a 15-mm nodule with ring-shaped enhancement in segment 8 of the liver. FDG-PET showed strong accumulation within the lesion. No other possible primary lesion or distant metastasis was detected. The patient was diagnosed with mixed hepatocellular carcinoma based on the preoperative imaging findings and underwent laparoscopic partial hepatectomy. Histopathological examination of the operative specimen showed aggregations of proliferating, small, round, atypical cells with a high nucleus/cytoplasm ratio. Immunohistological staining revealed that the tumor was positive for the mesenchymal cell marker vimentin, leading to a diagnosis of primary sarcoma of the liver. The pathological findings did not fit any existing classifications of sarcoma. The postoperative course was good and the patient remains relapse-free 15 months after surgery. Primary hepatic sarcomas are very rare. We report this case of resection of a primary hepatic sarcoma that did not fit with existing histopathological classifications of sarcoma.