[Benign salivary gland-type tumors of the bronchus: expression of high molecular weight cytokeratins]

Primary lung tumors showing features of salivary gland-type neoplasms are extremely rare, and their immunohistochemical profile has been seldom studied. We report two cases of bronchial pleomorphic and mucous gland adenomas and study the expression of markers such as TTF-1 and high molecular weight keratins in these tumors. Both tumors were endobronchial. The pleomorphic adenoma also had a well-circumscribed parenchymal component, with a biphasic morphology composed of epithelial and myoepithelial cells in a background of myxoid and hyaline stroma. The mucous gland adenoma displayed papillary and dilated glandular structures. In both cases, epithelial cells showed strong and diffuse cytoplasmic staining with high molecular weight cytokeratins (cytokeratin 5/6 and keratin 903), and lacked TTF-1 expression. This immunoprofile provides useful clues for the histogenesis of pulmonary benign salivary gland-type adenomas and helps in distinguishing them from primary adenocarcinomas in small biopsy specimens.