Dermatologic Manifestations of Glomus Tumor

Updated: May 26, 2016
  • Author: Jon H Meyerle, MD; Chief Editor: Dirk M Elston, MD  more...
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Overview

Background

Glomus tumors are rare soft tissue neoplasms that typically present in adults (ages 20-40 years) as small, blue-red papules or nodules of the distal extremities, with most cases involving subungual sites. These tumors are typically painful, often causing paroxysmal pain in response to temperature changes or pressure.

Note the images below.

Glomus tumor. Glomus tumor.
Multiple glomus tumors. Multiple glomus tumors.

Glomus tumors are thought to arise from the glomus body, a thermoregulatory shunt concentrated in the fingers and toes. Most lesions are solitary and localized to cutaneous sites; however, generalized glomuvenous malformations, or multiple glomangiomas, have also been described, and may have extracutaneous involvement.

While the vast majority of glomus tumors are benign, malignant cases have been rarely reported, with such cases typically being locally invasive, and with metastases being exceedingly rare. [1, 2, 3, 4]

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Pathophysiology

Glomus tumors are thought to represent hamartomatous proliferations of modified smooth muscle cells originating from preexisting normal glomus cell populations. Glomus cell populations are specialized arteriovenous anastomoses found most often in the fingers and are characterized by Sucquet-Hoyer canals, which play an important role in thermoregulation.

Interestingly, while glomus tumors predominate on the hands and fingers especially, these tumors can occur in a wide anatomic distribution, to include sites not known to contain glomus cells. One explanation for this finding is that these tumors may arise from perivascular cells that can differentiate into glomus cells.

Most glomus tumors are solitary and sporadic, but some cases of glomus tumor are multiple. These disseminated variants of glomus tumor, known as glomangiomas or glomuvenous malformations, differ clinically from glomus tumors in that they occur more often in children and adolescents, are typically multifocal, and do not have a predilection for subungual sites.

It is thought that glomangiomas and glomus tumors have different etiologies, with glomangiomas resembling venous malformations and containing more dilated venous channels than glomus tumors.

Note that most cases of glomangiomas manifest as sporadic tumors; however, familial cases with autosomal dominant inheritance patterns have also been described. Such familial glomangiomas have been mapped to 1p21-22 and are thought to result from loss-of-function mutations in the cytoplasmic protein glomulin. [5, 6, 7, 8]

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Epidemiology

Frequency

Glomus tumors account for 1-5% of all soft tissue tumors of the upper extremity, occurring in most cases in the nail bed [9] ; however, the true incidence of glomus tumors is unknown, likely as a result of misdiagnosis of many of these lesions as hemangiomas or venous malformations.

The multiple variant of glomus tumor — generalized glomuvenous malformations, or multiple glomangiomas — is much less common, accounting for less than 10% of all reported cases. [7] Such cases are seen more frequently in children, with the majority of patients reporting a positive family history.

Sex

Glomus tumors in general show no sex predilection; however, solitary subungual lesions are more commonly observed in women and multiple lesions are slightly more common in men.

Age

Solitary glomus tumors can occur at any age, but they are most frequent in young adults. Glomangiomas, or glomuvenous malformations, are often multifocal and typically present in children; indeed, many are congenitally present.

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Prognosis

The prognosis for patients with glomus tumors is excellent. Excision of painful lesions most often results in cure, with a low recurrence rate for solitary lesions. [10, 11]   Malignant glomus tumors are extremely rare and usually are locally aggressive. Their overall prognosis is good if they are treated with wide excision. However, metastases do occur and are associated with a very poor prognosis.

Patients with glomus tumors classically present with paroxysmal severe pain, often precipitated by cold, pressure, or dependency. Pain is more frequent in solitary lesions; multiple tumors—classically seen as glomuvenous malformations—arise in younger patients and tend to be asymptomatic.

In one report, a patient with more than 400 glomus tumors had thrombocytopenia as a result of platelet sequestration (ie, Kasabach-Merritt syndrome).

Extremely rare instances of malignant transformation within glomus tumors have been described; these typically represent a locally infiltrative malignancy; however, metastases have been described. [1, 2, 12, 13]

 

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