A case of primary adenosquamous carcinoma of the lung with marked bone formation

Abstract

We report a case of primary lung cancer with marked bone formation. A 75-year-old woman presented with a tumor shadow with marked calcification in the left upper lobe, which was detected on computed tomography. The patient received left upper lobectomy for the tumor, which tended to increase on follow-up. Pathological examination revealed the tumor to be adenosquamous carcinoma with marked bone formation. Primary lung cancer with bone formation is very rare, and there have been only 13 cases reported, including the present case. Adenosquamous carcinoma involved only the present case. Histological findings vary by case, many questions have been pointed out, and the mechanism of bone formation has been suggested to involve transforming growth factor type-β (TGF-β) and bone morphogenetic protein 2 (BMP2). The accumulation of further cases, discussed from various aspects, such as the mechanism, characteristics, and prognosis, is expected in the future.