Aggressive osteoblastoma associated with subgaleal hematoma.

A 26-year-old man with a chronic subgaleal hematoma containing calcific elements subsequently developed an aggressive osteoblastoma within the lesion. It is presumed that the osseous elements associated with the chronic process underwent neoplastic alteration. Such a lesion should be suspected in an individual with a long-standing subgaleal hematoma who reports changes occurring with respect to either size of the lesion or the development of tenderness.