Glomus tumor of the trachea. Report of a case with ultrastructural observation.

Extracutaneous glomus tumors are unusual and their occurrence in the trachea has been recognized with extreme rarity. We present a case of surgically resected glomus tumor of the trachea in a 54-year-old woman who was initially misdiagnosed as having bronchial asthma because of expiratory wheezing. The tumor, located 7 cm below the vocal cord and 5 cm above the carina, was an intraluminally protruding polypoid mass that measured 1.5 X 1.2 cm and arose from the posterior wall of the trachea with a broad base. Microscopically, the tumor was predominantly of the solid type, but a small proportion of a glomangiomatous component was admixed. Ultrastructural study confirmed the presence of myofibrillar bundles with focal densities and fine pinocytotic vesicles along the plasma membrane. A structure similar to a nonneoplastic glomus was demonstrated in the submucosal layer of the posterior wall away from the tumor margin. This suggests that the tracheal glomus tumor occurs more often in the posterior wall where neuromuscular complex structures may develop more readily.