Pulmonary metastasis from histologically benign giant cell tumor of bone. Report of a case diagnosed by fine needle aspiration cytology.

The cytologic features of pulmonary metastasis from a histologically benign giant cell tumor of bone are reported. The patient had undergone curettage of a benign giant cell tumor of the humerus two years earlier. Aspiration of a pulmonary mass yielded a cellular population of mononuclear stromal cells admixed with a smaller population of binucleate forms and occasional giant cells. Vacuolation and granulation of the stromal cells are cytologic features seen commonly in giant cell tumors of bone, but in the lung these features may deceptively mimic the appearance of pulmonary macrophages. Video thoracoscopic wedge resection of the metastatic lesion was performed subsequently.