A case report of primary intraosseous well-differentiated osteosarcoma of the rib

Abstract

Intraosseous well-differentiated osteosarcoma is a rare subtype of osteosarcoma associated with a much better prognosis than conventional osteosarcoma. The tumor commonly originates in the extremities. We report a very rare case of intraosseous well-differentiated osteosarcoma occurring in the ribs of a 70-year-old female. The patient underwent resection of the left anterior part of the sixth rib for fibrous dysplasia at the age of 33. At the age of 45, the patient underwent a second resection for the subcutaneous recurrence of fibrous dysplasia. At the age of 67, a chest computed tomography (CT) scan showed a 1.5-cm nodule arising from the surgical margin of the left sixth rib. Because the nodule increased to 3 cm after 3 years of follow-up, we suspected the tumor was a recurrence of fibrous dysplasia. We subsequently performed chest wall resection with an adequate surgical margin. The pathological diagnosis was intraosseous well-differentiated osteosarcoma. The patient had no additional adjuvant chemotherapy nor radiation therapy postoperatively. Over a short follow-up period, the patient has shown no signs of recurrence.