Fig. 2

Gross and histological findings of the pulmonary tumor. a Gross cut section. A white solid tumor with an irregular border and 25 × 12 × 10 mm in size. Bar, 10 mm. b Low-power view showing the tumor mainly in the soft tissue of the bronchial vascular bundle. The structure of the pulmonary artery was maintained inside the tumor. Hematoxylin and eosin (HE) stain. Bar, 2 mm. c Necrosis within the tumor. HE stain. Bar, 500 μm. d High-power view showing the sheet growth of monomorphic small round cells. Tumor cells had round to oval nuclei with distinct nucleoli and a scanty cytoplasm. Mitotic figures were easily found. HE stain. Bar, 100 μm