Glomus tumor of the trachea. Immunohistochemical and electron microscopic studies.

Glomus tumor of the trachea which developed in a 51-year-old man was reported. He experienced frequent episodes of respiratory infections and hemoptosis for 9 months. Bronchofiberscopic study demonstrated a polypoid tumor in the upper trachea. Local resection of the tumor was performed and it arised from the membranous portion of the third and fourth tracheal rings. Histologically, the tumor was composed of medium-sized rounded cells, resembling carcinoid tumor. Desmin and myosin immunoreactivities were found in most of the tumor cells. Electron microscopic examination showed that the tumor cells contained fine filaments with focal density, numerous pinocytotic vesicles along the plasma membrane and abundant mitochondria. The patient is well without evidences of tumor recurrence 2 years after the resection. This is the fourth report of the tracheal glomus tumor with definitive evidences of smooth muscle differentiation of the tumor cells.