Histologically verified lung metastases in benign giant cell tumours--14 cases from a single institution

From 1975 to 1997, 649 cases of benign giant cell tumours of the bone were treated at the Istituto Rizzoli. Fourteen patients (2.1%) experienced lung metastases after a mean of 35.2 months. The time interval between the diagnosis and the appearance of the lung metastases ranged from 3 months to 11.9 years. Metastasectomy was performed in all patients. Histologically, the metastases were identical to the primary bone lesions. Two patients with unresectable multiple metastases received additional chemotherapy. After a follow-up of 70 months (range: 8.2 to 185 months), all patients are alive. Ten patients showed no evidence of disease, one of these after a second resection of metastases, and four patients presented stable disease with multiple lung metastases. Local recurrence of the bone lesion occurred in seven patients before or simultaneously to the metastases. In contrast to previous reports, we could not detect a predominance of the distal radius, but all of the patients had a stage III tumour according to the Enneking criteria of benign lesions. We conclude that even metastatic benign giant cell tumours have an excellent prognosis after adequate resection. No prognostic factors despite high-grade lesions were detectable.