Figure 4

Histopathological characteristics and immunohistochemical features of the second case of pulmonary malignant melanoma: Histopathologically, the tumor was composed of malignant epitheliod tumor cells with large amounts of acidophilic cytoplasm and prominent nuclei. Mitotic figures were easily found. Lung tissue could be found in the surrounding of tumor cells (Figure 4A ×200and 4B ×400). Immunohistochemically, the tumor cells were positive for vimentin (Figure 4C ×200), S-100 protein (Figure 4D ×200), melanoma-pan (Figure 4E ×200), and HMB45 (Figure 4F ×200).