Pulmonary epithelial-myoepithelial tumor of unproven malignant potential: Report of a case and review of the literature

Epithelial-myoepithelial tumors of the lung are rare neoplasms whose biolog ical behavior and clinical course still remain to be defined. A case of epi thelial-myoepithelial tumor of the lung arising fi om bronchial mucosa-subm ucosa and occurring as a polypoid lesion of the upper left bronchus in a 47 -year-old man is reported The tumor did not infiltrate the cartilaginous wa d of the bronchus and showed a biphasic histological appearance with a doub le layering of epithelial and myoepithelial cells, Myoepithelial spindle ce lls with eosinophilic cytoplasm were also observed. Mitotic figures were ve ry rare and necrosis absent Immunohistochemical study for epithelial and mu scular markers confirmed the presence of a double-cell component in the tum or, namely epithelial and myoepithelial. The patient is alive and well, wit h no evidence of recurrent or metastatic disease 6 months after surgery. On the basis of the present case and the six previously reported cases, we su ggest using the noncommittal term pulmonary epithelial-myo-epithelial tumor of unproven malignant potential (PEMTUMP) for this type of neoplasm, In ad dition, we first introduce p63 as a novel marker for highlighting the myoep ithelial cells of the respiratory tract and speculate on the role of these cells in the development of this unusual tumor.