A lung metastasis from giant cell tumor of bone at eight years after primary resection.

We report a case of extensive pulmonary metastasis from a histologically benign giant cell tumor. A 34-year-old woman had undergone tumor resection, curettage and artificial bone grafting for giant cell tumor in the left tibia. At eight years after surgery, a chest radiograph revealed an extensive tumor shadow in the right thoracic cavity. Tumor resection with right upper and middle bilobectomy was performed. Its histological features were consistent with those of the primary tumor of the tibia. Distant metastases from a giant cell tumor of bone are rare, with only 50 reported cases. Metastasis has occurred mainly within 3 years after the primary resection. However, in 20% of reported cases, metastasis occurred after 5 years or longer. Long-term follow-up and careful observation for distant metastasis are necessary for this histologically benign disease.