A resected case of primary pulmonary epithelial-myoepithelial carcinoma

Abstract

A 58-year-old man was referred to our hospital because of a nodule in the left lower lung detected by chest-Xp. CT showed a 20-mm round tumor in the left S8. Bronchoscopic findings revealed a smooth-surface tumor obstructing the orifice of B8b in the left lower lobe. The preoperative diagnosis was a salivary gland tumor based on a biopsy specimen. We performed a left lower lobectomy by three-port complete VATS. Histological examination revealed that the tumor showed a biphasic proliferation of myoepithelial cells and glandular epithelial cells. The former form a small ductal or alveolar structure, and the latter proliferate in the lumen of that ductal structure. Immunohistochemical staining was positive for cytokeratin AE1/AE3 in most epithelial cells, positive for p63 in most cells, positive for SMA in a part of myoepithelial cells, and also positive for S-100 in a part of myoepithelial cells. We diagnosed this tumor as primary epithelial-myoepithelial carcinoma of the lung. There had been no recurrence as of one year after the surgery.