<Case Report>A Case of Fibrous Histiocytoma of the Liver

Abstract

Malignant fibrous histiocytoma (MFH) is a rare disease. We describe a 68-year-old man admitted to the hospital because of malaise. On admission, hematologic and serum chemical examinations showed no abnormalities. A tumor measuring 6.0×6.0×5.5 cm was found in segment S6 of the right lobe of the liver. A computed tomographic scan of the abdomen revealed a mass surrounded by a capsule-like region with a nonuniform shadow at its margin. The mass contained a nonuniform low density area. A magnetic resonance imaging scan showed low intensity on T1-weighted images and high intensity on T2-weighted images. An angiograrn of the abdomen revealed a tumor with a darkly stained margin during the venous phase. Partial resection of the liver, including S6 and part of S7, was performed. On histopathological examination, this case was characterized by a storiform pattern. The inside of the tumor showed a storiform-pleomorphic pattern with inflammatory cell infiltration and partial mucinous degeneration. On immunohistochemical studies, the tumor cells stained positively for CD6. The diagnosis was MFH.

肝原発の悪性線維性組織球（MFH）はまれな疾患である. 患者は68歳の男性. 主訴は倦怠感. 入院時検査では血液検査で異常を認めなかった. 腫瘍は肝右葉 S6 にあり大きさは 6.0×6.0×5.5cm 大であった. 腹部CT検査で辺縁部は不均一な造影効果を伴う被膜状のものを認め, 内部は不均一な low density area であった. MRI検査ではT1強調画像で low intensity, T2 強調画像で high intensity として描出された. 腹部血管造影は, 辺縁が静脈相で濃染される腫瘍像を認めた. S6 と S7 の一部を含む肝部分切除を施行した. 病理組織学的検査は, 線維芽細胞様細胞と組織球様細胞とからなる特徴的な storiform pattern （花むしろ模様）が見られ, 腫瘍内には炎症性細胞浸潤や一部粘液変性を伴う storiform pleomorphic type （花むしろ多形型）であった. 免疫組織化学的検査は CD68 に陽性を示したことより MFH と診断した．