EPITHELIAL-MYOEPITHELIAL CARCINOMA OF THE BRONCHUS

An extremely rare case of epithelial-myoepithelial carcinoma (EMC) of a lobar bronchus in a 47-year-old female is reported. Grossly, the tum or formed a polypoid mass obstructing the bronchial lumen. Microscopic ally, it was composed of two cellular types - epithelial cells with eo sinophilic cytoplasm and clear myoepithelial cells. Numerous tubules f ormed by an inner epithelial and outer myoepithelial layer were found. Focally, the tumor showed solid growth of clear cells. Prominent hyal inization of the stroma was found. The nature of the cells was confirm ed by positive expression of cytokeratins and epithelial membrane anti gen in epithelial cells and vimentin and smooth muscle actin in myoepi thelial cells. Differential diagnosis of EMC includes a broad spectrum of salivary gland-type tumors. Furthermore, metastases of clear cell carcinoma of the kidney or thyroid, clear cell (''sugar'') tumor of th e lung, glandular form of carcinoid, bronchioalveolar adenocarcinoma w ith myoepithelial cells and pulmonary adenosquamous carcinoma with amy loid-like stroma must be distinguished from EMC. The tumor has neither recurred nor metastasised, a fact supporting the current opinion, tha t EMC is a tumor of low grade malignancy.