Figure 1

The histological features and immunohistochemical staining patterns of the present mucoepidermoid carcinoma of the lung. A: The cysts of the present tumor were variable sizes and contained plentiful mucus. The mucus-secreting cells admixed among the cysts and nests regions were large and had light blue-gray mucinous cytoplasm (H&E ×200). The right bottom is a focal high power field of figure A (H&E ×400). B: The glands and nests regions were composed by the intermediate cells, which were polygonal shape, had round bland nuclei and faint eosinophilic cytoplasm (H&E ×200). C: The inner lining cells of the glandular structures were uniform cuboidal and hobnail-like, had oval and bland nuclei, similar to the Type II alveolar epithelia (H&E ×400). D: The squamoid cells admixed with intermediate cells and formed some nests in a sheet-like pattern (H&E ×400). E: Low-molecular-weitht cytokeratin was strongly positive in all tumor cells (×400). F: P63 was strongly positive in most of the tumor cells except of the inner lining cells of glandular structures (×400). G: Thyroid transcription factor-1 was only limited to the inner layer cells of the glandular structures (×400). H: Surfactant protein-B was strongly positive in the inner layer cells and some outer layer cells of glandular structures (×400).