A rare case of malignant chondromyxoid fibroma developed in the scapula of a woman who was treated with interscapulothoracic resection. When a biopsy specimen was submitted for study, difficulty was encountered in establishing the histologic diagnosis. A large dose of radiation was given before surgery, based on an original biopsy diagnosis of osteosarcoma; in retrospect, preoperative irradiation probably was contraindicated. Two years and four months after surgery, the patient was working with no evidence of recurrence or metastasis.