Calcification has long been a determinant in the radiologic distinction of a benign pulmonary mass. However, rare examples of calcification without ossification in pulmonary adenocarcinoma and ossification in the bronchial carcinoid have led some investigators to warn against this approach. A case of pulmonary adenocarcinoma with stromal ossification is reported herein. The literature is reviewed for neoplasms that exhibit pulmonary ossification either by primary or metastatic lesions. To our knowledge, this case represents the first report of benign osseous stromal metaplasia in the primary lesion of a pulmonary adenocarcinoma.