Giant cell carcinoma of the lung was first described in detail by Nash and Stout1 in 1958 in a report of five cases. They pointed out that inasmuch as the exact nature of this tumor was not established, it should be given special recognition until more was learned concerning its behavior. Since then more attention has been given to it and at least 118 cases have been reported.1-3 The nature of the tumor, because of its morphological resemblance to mesodermal tumors, especially rhabdomyosarcomas, was early in question, even though Hadley and Bullock14 in 1953 had referred to it as a subdivision of anaplastic carcinomas without detailing its morphological appearance. In 1961, its epithelial origin was confirmed by tissue culture.4 Since then tumors showing both squamous and adenomatous features7,11 as well as undifferentiated tumors, have been reported as giant cell carcinomas without the benefit of clearly