Primary Hepatic Synovial Sarcoma with Synchronous Colorectal Adenocarcinoma: A Case Report and Review of Literature

Background: : Primary hepatic synovial sarcoma is an extremely rare disease with a poor prognosis. The symptoms are nonspecific, and it is usually diagnosed at an advanced stage. Case presentation A 63-year-old male patient was admitted with asymptomatic but elevated Alpha Fetoprotein (AFP) serum level in routine medical examination with a medical history of Hepatitis B with Tenofovir 300 mg per day. No sign of jaundice was observed. Her abdomen was flat and soft without tenderness or palpable mass. Dynamic abdominal computed tomography (CT) scan and magnetic resonance imaging (MRI) showed a hypervascular 15 x 26 mm mass within hepatic subsegment V. There was no distant spread location. Colonoscopy revealed 3-cm sessile polyp in Sigmoid colon with pathological result was adenocarcinoma. Immunohistochemistry was performed to accurate diagnosis. The tumor cells were positive for CD99, EMA and a Ki67 value of 40% and were negative for Hepar-1, CD34, CD117, CK7, STAT6, DOG1, SMA and S100. The final diagnosis for this patient was a Malignant Sigmoid-colon polyp with a Primary hepatic synovial sarcoma. Laparoscopic Sigmoid-colon and rectal resection with injecting autologous blood to mark the tumor before surgery was performed for malignant polypectomy lesion and Hepatic Radiofrequency Ablation (RFA) was performed four days before surgery. With no postoperative complications as well as acute hepatic failure, the patient was discharged on the POD8 uneventfully. Conclusion: A primary hepatic synovial sarcoma is especially rare, with the present case being the fifth accounted in the English literature. Synovial sarcoma (SS) is a genetically soft tissue sarcoma with uncertain differentiation and originated from primitive mesenchymal cells. We here present a report of this case with had primary hepatic synovial sarcoma synchronously with a colorectal adenocarcinoma.