両上腕骨に脆弱性骨折を生じた小児大腿骨骨肉腫の1例

Bilateral Insufficiency Fracture of the Humerus in a Child with Osteosarcoma of the Distal Femur : Case Report

　抄録：われわれは左大腿骨骨肉腫の患肢温存手術後，両上腕骨に脆弱性骨折を生じた1例を経験した．症例は7歳の男児である．術前化学療法を1クール施行し，腫瘍切除とパスツール処理骨による患肢再建を行った．術後化学療法は4クール施行した．パスツール処理骨の骨癒合が遅れたため，両松葉杖による免荷を指示した．術後8カ月で右上腕骨に，術後18カ月で左上腕骨に脆弱性骨折を生じた．上肢の脆弱性骨折は稀であるが，松葉杖使用中の小児骨肉腫患者では注意を要する．脆弱性骨折の基盤にはmethotrexate osteopathyがあると思われた．

　Background：Reports of symptomatic insufficiency fracture of the upper extremity are rare. We report the case of a boy with osteosarcoma of the left distal femur who developed insufficiency fractures of both humeri during postoperative rehabilitation. Case Presentation：A 7-year-old boy complained of left thigh pain and was diagnosed with osteosarcoma of the left distal femur. After one course of neoadjuvant chemotherapy, the tumor was excised and the extremity with reconstructed with a pasteurized autologous bone graft. Surgery was followed by 4 courses of adjuvant chemotherapy. Bone union was poor, and the patient required axillary crutches without weight-bearing. The patient developed insufficiency fractures of the right humerus and left humerus at 8months and 18months, respectively, after the operarion. Conclusion：Insufficiency fractures should be considered during the postoperative rehabilitation of pediatric patients with osteosarcoma treated with systemic chemotherapy. Insufficiency fractures associated with methotrexate osteopathy may occur not only in the lower extremities but in the upper extremities as well.