Electron microscopic examination of fibroblastic osteosarcoma accompanied by unusual osteosarcoma: With special reference to its comparison with malgnant fibrous histiocytoma

Usually, osteosarcoma is histologically divided into osteoblastic type, chondroblastic type, fibroblastic type, telangiectatic type and the like. Recently, we experienced a case which had left gonalgia as chief complaint after 6 years of observational treatment of Hypophosphatemic Vitamin D Resistant Osteomalacia and was diagnosed by biopsy as lateral condyle - originated fibroblastic osteosarcoma comprising spindle cells together with mailgnant osteoid. Resected material after chemotherapy revealed storiform pattern of solid tumor comprising spindle cells. We made comparative, electron microscopic and histochemical examinations of this case and malignant fibrous histiocytoma (MFH) of our case. We would like to report the results obtained.