EPITHELIAL-MYOEPITHELIAL CARCINOMA OF THE LUNG - IMMUNOHISTOCHEMICAL AND ULTRASTRUCTURAL OBSERVATIONS AND REVIEW OF THE LITERATURE

Epithelial-myoepithelial carcinoma is a rare lo iv-grade malignant sal ivary gland neoplasm that most commonly occurs in the parotid gland bu t can also arise in minor salivary glands. We report a case of a prima ry epithelial-myoepithelial carcinoma of the lung, The patient is a 55 -year-old black woman who presented with increasing shortness of breat h and productive cough of at least 3 months duration, A left lower lob e endobronchial lesion was identified radiographically, Surgical resec tion of the lesion was performed, obtaining a circumscribed, nonencaps ulated 3.9 cm tan mass which was attached to the inner wall of the lat eral basal segment bronchus, A biphasic proliferation of epithelial (c ytokeratin positive; S-100 protein and muscle-specific actin negative) and myoepithelial (S-100 protein and muscle-specific actin positive w ith focal weak cytokeratin positive) cells was identified by immunohis tochemical and ultrastructural analysis of formalin-fixed tissue, The patient is disease free 7 months after resection, Pulmonary epithelial -myoepithelial carcinoma likely derives from the submucosal bronchial glands and should be added to the growing list of salivary gland-type neoplasms that may occur as primary pulmonary neoplasms, Because its h istology is identical to salivary epithelial-myoepithelial carcinoma, pulmonary epithelial-myoepithelial carcinoma should be considered a lo w-grade malignant neoplasm and should be designated as epithelial-myoe pithelial carcinoma in preference to other terms that may not convey i ts malignant potential, Although follow-up on reported cases is limite d, lobectomy with negative bronchial margin should be curative.