Primary lymphoma and Paget's disease of the femur.

Malignant neoplasms associated with Paget's disease of the bone are most commonly metastatic and rarely primary malignant transformations. Sarcomatous transformations, such as osteogenic sarcoma, predominant in Paget's disease. The authors discuss the synchronous and synostotic occurrence of a primary lymphoma of bone in association with Paget's disease. The simultaneous occurrence of isolated primary lymphoma of bone and its phenotype in association with Paget's disease in the femur, which had not been rigorously documented in the previous literature, is reported.