Intracortical small cell osteosarcoma.

A case of intracortical osteosarcoma, a rare form of osteosarcoma that may radiologically simulate a variety of benign and malignant bone lesions, is described. To date, all cases have arisen in the diaphysis of either the tibia or femur, and histologically have been of osteoblastic type. In contrast, the current tumor was a small cell osteosarcoma, another uncommon variety of osteosarcoma. A summary of the reported cases of intracortical osteosarcoma is given, and the literature on small cell osteosarcoma is briefly reviewed.