Osteosarcoma Arising in a Solitary Osteochondroma of the Fibula

Abstract

We present a case of osteosarcoma arising in an osteochondroma of the right fibula in a 30-year-old woman. The available radiographic studies of the lesion were not suggestive of malignant transformation. The lesion and underlying bone were excised. Histologic examination showed a conventional high-grade osteoblastic osteosarcoma that focally eroded the fibrocartilaginous cap. The patient received postoperative chemotherapy and shows no evidence of disease 27 months following operation. The occurrence of osteosarcoma in an osteochondroma is an extremely rare event, and only a few cases are on record in the literature.

Secondary Peripheral Dedifferentiated Chondrosarcoma

“…Osteosarcoma and MFH (UPS) are reported to arise secondarily from the bone stalk. Interestingly, these tumors have been reported to arise from osteochondroma without the presence of lowgrade CS [19][20][21] . These tumors are distinguished as secondary high-grade sarcomas associated with osteochondromas being different from secondary peripheral dedifferentiated CS.…”

Sino-orbital osteochondroma with malignant transformation to osteosarcoma

“…Although osteochondroma can undergo malignant transformation to chondrosarcoma in 1–2% of cases, 8 transformation to osteosarcoma is extremely rare with very few cases reported in the literature. 8 , 9 This distinction is important, especially for orbital disease, because osteosarcomas generally respond more favorably to chemotherapy than chondrosarcomas. 1 , 10 This may open up options for globe-sparing treatment in select cases.…”

Unusual location of osteochondroma in the temporal region in a patient with functional pituitary adenoma

“…1,3 Rarely, other malignant tumours such as osteosarcoma can complicate an osteochondroma. 30 Osteochondromas are usually diagnosed by plain radiographs. The key radiological features are cortical and marrow continuity between the lesion and the parent bone and the presence of a cartilage cap.…”