Glomus tumor was also the name formerly used for a tumor now called a paraganglioma

Paraganglioma

A paraganglioma is a rare neuroendocrine neoplasm that may develop at various body sites . About 97% are benign and cured by surgical removal; the remaining 3% are malignant because they are able to produce distant metastases...

.

A glomus tumor (also known as a "solitary glomus tumor," "solid glomus tumor," glomangioma, and nonchromaffin paraganglioma) is a rare benign

Benign

A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...

 neoplasm arising from the glomus body

Glomus body

A glomus body is a component of the dermis layer of the skin, involved in body temperature regulation. The glomus body consists of an arterio-venous shunt surrounded by a capsule of connective tissue. Glomus bodies are most numerous in the fingers and toes...

. Glomus tumors were first described by Hoyer in 1877, while the first complete clinical description was given by Masson in 1924.

Familial glomangiomas have been associated with a variety of deletions in the glomulin

GLMN

Glomulin is a protein that in humans is encoded by the GLMN gene.-Interactions:GLMN has been shown to interact with FKBP52, C-Met and FKBP1A.-Further reading:...

 gene, and are inherited in an autosomal dominant manner, with incomplete penetrance.

Presentation

They are usually solitary and small, and can be found under the fingernails. They can also be found on the tympanic membrane.

They are often painful, and the pain is reproduced when the lesion is placed in cold water.

These tumors tend to have a bluish discoloration, although a white appearance is also noted. Elevation of the nail bed can occur

In rare cases, the tumors may present in other body areas, such as the gastric antrum or glans penis

Glans penis

The glans penis is the sensitive bulbous structure at the distal end of the penis. The glans penis is anatomically homologous to the clitoral glans of the female...

. Treatment is essentially the same.

Frequency

The exact incidence of glomus tumors is unknown. The multiple variant is rare, accounting for less than 10% of all cases. The probable misdiagnosis of many of these lesions as hemangiomas or venous malformations also makes an accurate assessment of incidence difficult.

Mortality/Morbidity

The most common adverse effect is pain, which is usually associated with solitary lesions. Multiple tumors are less likely to be painful. In one report, a patient with more than 400 glomus tumors had thrombocytopenia as a result of platelet sequestration (ie, Kasabach-Merritt syndrome). Malignant glomus tumors, or glomangiosarcomas, are extremely rare and usually represent a locally infiltrative malignancy. However, metastases do occur and are usually fatal.

Sex

Solitary glomus tumors, particularly subungual lesions, are more common in females than in males. Multiple lesions are slightly more common in males.

Age

Solitary glomus tumors are more frequent in adults than in others. Multiple glomus tumors develop 10–15 years earlier than single lesions; about one third of the cases of multiple tumors occur in those younger than 20 years. Congenital glomus tumors are rare; they are plaquelike in appearance and are considered a variant of multiple glomus tumors.

Malignant glomus tumors

Malignant glomus tumors, histologically and/or clinically are exceedingly rare. Criteria for the diagnosis of malignancy in glomus tumors are:

1. Tumor size of more than 2 centimeters and subfascial or visceral location.
2. Atypical mitotic figures.
3. Marked nuclear atypia and any level of mitotic activity.
   • • Pericytes of Zimmerman

Malignant glomus tumors have been subdivided into three categories based on their histologic appearance: locally infiltrative glomus tumors (LIGT), glomangiosarcomas arising in benign glomus tumors (GABG), and glomangiosarcomas arising de novo (GADN).

A few cases of malignant glomus tumors have been reported; however, they are usually only locally invasive, and metastases are exceedingly rare. Brathwaite et al in 1996 reported widespread metastases of a malignant glomus tumor involving the skin, lungs, jejunum, liver, spleen, and lymph nodes. Another report of a malignant glomus tumor with metastases is that of Watanabe et al., who reported a cutaneous malignant glomus tumor with widespread metastases. A few other cases of malignant glomus tumors have been reported in the literature usually occur in the older age group, and have been described at several locations, primarily the soft tissues and gastrointestinal tracts.

Recently, Lamba G et al reported the first case of malignant glomus tumor arising from the kidneys.

Treatment

Radiation therapy and surgery can be involved in the treatment of these tumors.

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