[Giant-cell tumor of the patella with lung metastases: a case report].

Giant-cell tumors are an infrequent clinical, radiological, and pathological entity observed in 5% of primary bone tumors. They generally occur at the epiphysis of long bones, particularly in the knee area but patellar localization seems very rare. Despite their perfectly benign histological aspect, giant-cell tumors may be aggressive, leading to local recurrence or even distant metastasis to the lung. We report a case of benign giant-cell tumor of the patella with lung metastasis observed in a 23-year-old woman. The aggressive radiological image was suggestive of chondrosarcoma. Histologically the differential diagnosis with chondroblastoma was difficult. The tumor and lung metastasis were treated by surgical resection. Four years later there has been no recurrence. We present the anatomic and clinical aspects of giant-cell tumor of the bone together with the diagnostic approach and the clinical course.