Contributor: Norman C. Charles
Glomangiomyoma (glomus tumor, glomangioma, glomus cell tumor) is an uncommon, hamartomatous, usually benign neoplasm whose cells resemble the modified smooth muscle cells of the normal glomus body. The tumor was first described in 1924 by Masson who suggested that the lesion represented an overgrowth of the normal glomus body. Glomus bodies are contractile intravascular shunts scattered amidst the skin probably concerned with thermoregulation of peripheral circulation. They are abundant in exposed acral points like the balls of the digits, the tip of the nose and pinnae of the ears where the ratio of surface area to tissue bulk is large. Interposed between the arterial and venous sides of the shunt is the S-shaped Sucquet-Hoyer canal, whose wall beyond the endothelium contain several layers of contractile glomus cells intermixed with variable numbers of smooth muscle cells. Glomus cell tumors  are red-to-blue intradermal nodules, characteristically found in the subungual portion of the finger and also the palm, wrist, forearm and foot. 90% are solitary, occurring in young adults, although multiple asymptomatic tumors may appear in childhood. Rarely glomus cell tumors appear as single purplish lesions of the eyelid and conjunctiva, as well an intraorbital mass. As elsewhere in the body, solitary lesions are more common than multiple glomus cell tumors. Horner syndrome is a rare association. Multiple cutaneous facial and palatal lesions have been reported. Tenderness and purplish vascularity are clues, although not always present. Lesions may be misdiagnosed as the more common hemangioma, lymphangioma, or varix until histopathologic examination is performed, disclosing the distinctive glomus cells.