Stromal reactions including benign osteoclast-like giant cells are rarely seen within carcinomas. They are even extremely rare in lung carcinomas.

A 61-year-old male patient who had marked volume loss in the right lung radiologically was admitted. Fiberoptic bronchoscopy was performed, an endobronchial lesion arising from the right upper lobe bronchus and nearly completely obstructing the right main bronchus was detected and multiple biopsies were taken. Histopathological examination of these biopsies confirmed a non-small cell carcinoma with osteoclast-like multinuclear giant cells. A sleeve upper lobectomy was performed through a right thoracotomy. Histopathological examination of the specimen showed “poorly differentiated squamous cell carcinoma and osteoclast-like multinuclear giant cells within”. The patient is well and disease-free 42 months after the operation.

There are numerous cases of osteoclast-like giant cells reported within the breast, thyroid, liver, gall bladder, stomach, pancreas, urinary bladder and endometrium but they are very rare within lung carcinomas. A diagnosis of lung carcinoma with osteoclast-like giant cells is very important as it may cause diagnostic confusion with giant cell carcinomas and foreign body type stromal reactions.