A glomus tumor is a rare benign tumor of the hand. It constitutes 1–5% of the soft-tissue tumors in the hand. It arises from the glomus body which is a neuromyoarterial apparatus described by P. Masson in 1924. The normal glomus body is an arteriovenous shunt that is composed of an afferent arteriole, an anastomotic vessel (Sucquet-Hoyer canal), a collecting vein, and a capsular portion. It resides in the stratum reticulum of the skin. There are large numbers in the subungual region and in the distal pad of the digits. The glomus body is a controlled arteriovenous anastomosis or shunt between the terminal vessels thought to be important in regulating peripheral blood flow in the digits, which secondarily controls peripheral blood pressure and body temperature. (photo credit)
Glomus tumors affect women two to three times more often than men. Most are in the 30-50 year age group. Most occur in the subungual area (approximately 50%), but can occur on the finger tip pulp, the palm, wrist, forearm and foot. Glomus tumor can occur near the tip of the spine, where it may arise from the glomus coccygeum. Glomus tumors have also been described in locations where the glomus body does not normally occur. These unusual sites include the patella, bone, chest wall, eyelid, colon, rectum, and cervix. Over 75% of glomus tumors occur in the hand.
Symptoms usually consist of a triad
- severe paroxysmal pain--the pain can be excruciating and is described as a burning or bursting
- localized tenderness
- extreme cold sensitivity
Physical exam reveals a blue-pink tender mass that can often be seen through the nail plate or skin. When the mass is growing beneath the nailbed (subungual), it can displace the nailbed dorsally. (photo credit) When the lesion is beneath the nail matrix, it can produce a longitudinal ridging of the nail plate. Placing the involved digit or extremity in ice water will reproduce the pain within 60 seconds. Typically, the mass is usually less than 7 mm in diameter, so can be very difficult to palpate even when not beneath the nail. There are two clinical findings described, particularly in relation to the painful subungual solitary glomus tumors. They are the Hildreth's sign and Love's test. Hildreth's sign is disappearance of pain after application of a tourniquet proximally on the arm. Love's test consists of eliciting pain by applying pressure to a precise area with the tip of a pencil. Routine laboratory studies have no role in diagnosis of glomus tumor.
X-rays of the finger may show bone erosion, ranging from a small concave defect to a sharply defined radiolucent lesion seen in the region of the tuft of the phalanx. There is often a thin sclerotic margin about the defect as a secondary reaction to the tumor pressure. Standard magnetic resonance imaging (MRI) can be used to detect glomus tumors. (photo credit)
The tumor consist of a highly organized, well-encapsulated mass consisting of glomus cells, curled blood vessels, and a large number of nerves within or adjacent to the lesion. This explains the great sensitivity of the glomus tumor.
Treatment is surgical. Surgical approach will vary depending on the location of the tumor. The glomus tumor is always well encapsulated and can usually be "shelled out" with little or no difficulty. When excision is complete, the prognosis is excellent for full recovery with no recurrence.
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Two cases of subungual glomus tumor; Murthy PS, Rajagopal R, Kar PK, Grover S; Indian J Dermatol Venereol Leprol 2006;72:47-9
Glomus Tumor by Michael B Reynolds, MD--eMedicine Article