Juxtacortical dedifferentiated chondrosarcoma from a primary periosteal chondrosarcoma
Mitchell, A.; Rudan, J.R.; Fenton, P.V.
Modern Pathology An Official Journal of the United States and Canadian Academy of Pathology Inc 9(3): 279-283
1996
ISSN/ISBN: 0893-3952 PMID: 8685228 Document Number: 455911
In this report, we describe dedifferentiation in a primary periosteal chondrosarcoma in the proximal tibia of a 73-year-old man. The diagnosis of primary periosteal chondrosarcoma was made by the characteristic radiographic, gross, and microscopic features of the tumor. The presence of dedifferentiation, however, in the form of malignant fibrous histiocytoma, was an unexpected histologic finding. Although rare, dedifferentiation is a well-recognized occurrence in secondary chondrosarcomas arising from precursor osteochondromas. This event has not been previously documented in the setting of primary periosteal chondrosarcoma.