Fig. 2

Macroscopic and microscopic findings of the pulmonary nodule. a, b A 22 × 18 × 12-mm nodule was found in the left lower lobe of the lung. c, d Pathological investigation revealed a dense sheet-like growth of small tumor cells with scant cytoplasm and finely granular nuclear chromatin. e There was also a sheet-like growth of bizarre, highly pleomorphic mono- or occasionally multinucleated giant cells. HE, hematoxylin and eosin, G giant cell component, S small cell component