CASE REPORT: Epithelial-myoepithelial carcinoma of the bronchus

Abstract

Pulmonary epithelial-myoepithelial carcinoma is a rare low-grade malignant neoplasm that has the characteristic histologic features, epithelial and myoepithelial differentiation, similar to the salivary gland counterpart. This tumor is thought to arise from bronchial submucosal glands distributed throughout the lower respiratory tract. We recently experienced a case of epithelial-myoepithelial carcinoma of the bronchus in a 61-year-old man. Computed tomography of his chest revealed an endobronchial mass in the bronchus of the left lower lobe. The lobectomy specimen showed a solitary endobronchial mass, measuring 2.3 cm in greatest diameter. Histologically, the tumor was composed of variable proportions of epithelial and myoepithelial cells. The epithelial cells represented an inner layer of duct-like structures and the outer clear cell layer was myoepithelial-type cells. The epithelial cells were positive for pancytokeratin and the clear myoepithelial cells were positive for vimentin, alpha-smooth muscle actin and S-100 protein. Finally our diagnosis was epithelial-myoepithelial carcinoma of the bronchus.