Primary tumors of the patella. A review of 42 cases.

This study reports 42 cases of histologically proven and radiographically correlated primary patellar tumors. Despite diverse histologic diagnoses, the radiographic appearances of benign as opposed to malignant patellar neoplasms are essentially indistinguishable. Although the literature suggests that giant cell tumor is the most frequent benign tumor of the patella, the most common benign neoplasm in this series is chondroblastoma (16 cases). Only four primary malignant lesions were encountered, three cases of lymphoma and one case of hemangioendothelioma. Since 38 (90%) of the 42 cases were benign, a benign etiology should be strongly favored, notwithstanding the radiographic appearance, whenever a primary patellar tumor is encountered.