Dumbell型発育を呈した胸壁原発malignant fibrous histiocytoma（MFH）の1例

Primary Malignant Fibrous Histiocytoma of the Chest Wall Characterized by the Dumbell-Shape Growth

　54歳，男性で左側胸部痛を主訴に来院．左後腋下線第5肋間に10cm径の弾性軟の腫瘤を触知し，X線CT上第5肋間中心にdumbell型に発育した腫瘤を認め，中心部壊死を疑う低吸収域と周囲のCE効果を呈した．広背筋，肩甲骨とは脂肪層を介して境され，骨破壊や肺浸潤所見は認めなかった．MRIではT1T2ともhigh intensityを呈し，内部にlow　intensity部混在を認めた．血管造影では左第5肋間動脈よりfeedingされ胸背静脈にdrainageされる腫瘤濃染像を認めた．Echo下に経皮針生検を行いMFH（giant cell type）の診断を得た．体表で唯一触知した左腋下リンパ節の生検および⁶⁷Ga scintigraphyでは転移を疑う所見は認めなかった．手術は分離換気下に右側臥位とし，広背筋の一部と前鋸筋を含み，腫瘤縁から5cm離した第4肋骨から第7肋骨までの胸壁全層切除とし，欠損部分の再建術も併せて行った．

A rare case of malignant fibrous histiocytoma (giant cell type) in a 54 year-old man was presented. The tumor was localized at the left side chest wall and had grown through the 5th intercostal space, showing dum-bell shape. Prior to operation, this lesion was well evaluated by X-ray, CT, MRI, angiography, scintigra-phy and needle biopsy. The tumor was covered by thin fascia and well bordered with surrounding tissue, in-dicating no bone invasion or metastasis. Angiogra-phically, it was fed from the dilated left 5th intercostal artery and drained into the 5th intercostal vein and thoraco-dorsal vein. An extended excisional operation, including 4th-7th rib cage without lobectomy, was performed and the large chest wall defect was recon-structed with coverage of a Goretex sheet and a latis-simus dorsi musculocutaneous flap.