頭蓋骨転移を来した大腿骨骨肉腫の1例

Cranial Metastasis by an Osteosarcoma of the Femur. Case Report

　70歳の女性の初診時，明らかな遠隔転移のない右大腿骨骨肉腫に対して，広範切除および人工膝関節置換術を行った．術後6カ月頃より，右頭頂部の無痛性腫脹が出現し，急速に増大した．単純CTで，頭頂骨の破壊像と骨外腫瘍を認めた．造影MRIで，硬膜や脳実質への浸潤が疑われた．切開生検の組織像から，骨肉腫の転移と診断した．頭頂骨開頭術を行い，腫瘍は，皮膚，頭蓋骨，硬膜とともに一塊にして摘出した．欠損部は人工硬膜，プレートで形成し，遊離広背筋皮弁と植皮で覆った．急速に多発骨転移を来し，発症4カ月で死亡した．

　A 70-year-old woman with non-metastatic osteosarcoma of the femur was treated by distal femoral resection and endoprosthetic reconstruction. Six months after surgery, she reported painless bulging of the side of her head. The tumor grew rapidly. Non-contrast CT revealed that the tumor had destroyed the parietal bone, and that extended from the epidural space to the scalp. Involvemant of the dura mater and brain was suspected based on the Gd-enhanced MRI findings. The histological diagnosis was metastatic osteosarcoma based on examination of an open biopsy specimen. Treatment consisted of craniotomy and en-bloc resection of the tumor with scalp, cranium, and dura mater followed by cranioplasty with artificial dura mater and a titanium plate covered by a free latissimus dorsi flap and skin graft. However, multiple metastatic bone lesions were detected soon after surgery, and the patient died 4 months after she first presented.