Osteosarcoma of the Distal Femur in an Elderly Patient for Which Diagnosis was Difficult

Abstract

We report a 64-year-old woman who was referred to our institution for treatment after X-ray images showed an osteolytic lesion in the right distal femur at a local clinic. She had first felt pain in the right knee about one year previously, and nine months later she visited the local clinic when her pain worsened. She had no notable medical history. Incisional biopsy indicated malignancy, although the diagnosis was not definitive. Wide excision of the tumor lesion and artificial joint replacement of the right knee were performed. Pathological examination proved that the removed tissue specimen was osteosarcoma, and therefore, cisplatin and adriamycin were administered as postoperative chemotherapy. No recurrence was noted eight months after surgery. While reports of primary osteosarcoma in elderly patients have been increasing, it remains a rare tumor. Special attention is important in the diagnosis of osteosarcoma, as delay may result in deterioration of the condition and a poorer prognosis.