Radiological differential diagnosis of osteolytic lesions in the patella include non-neoplastic conditions, and benign and malignant neoplasms. Non-neoplastic conditions include dorsal defects, hyperparathyroidism, osteomyelitis, osteochondritis dissecans, and rheumatoid cysts. Benign lesions include chondroblastoma, giant cell tumors, simple bone cysts, hemangioma, osteochondroma, lipoma and osteoblastoma. Malignant tumors include lymphoma, hemangioendothelioma and metastases.
Take Home Message-The patella should not be regarded as an unexpected location for a characteristically epiphyseal lesion such as a giant cell tumor.