What are the other Names for this Condition? (Also known as/Synonyms)

• Glomus Tumor of Nail Bed
• Glomus Tumor of Nail Matrix
• Glomus Tumor of Nail Unit

What is Subungual Glomus Tumor? (Definition/Background Information)

• Glomus tumors are a group of uncommon tumors caused by the proliferation of glomus cells, which are found in the glomus body. The glomus body is a small organ found in large numbers all over the body (and even in the fingers and toes). It controls and helps regulate the body temperature and blood flow
• Subungual Glomus Tumor is a type of glomus tumor of the nail affecting the tissue beneath the nail. It is also known as Glomus Tumor of Nail Unit and can affect either the fingernail or toenail
• The affected nail bed may be swollen and bluish in color. In severe cases, deformity of the nail is observed. They are also generally painful. Subungual Glomus Tumors are mostly seen in young adult women
• The exact cause of tumor formation is not known, though several genetic mutations have been identified. If more than one finger or toe is affected (multiple digits are involved), then the condition may be associated with the genetic disorder neurofibromatosis type 1 (NF1)
• Surgical removal of Subungual Glomus Tumor is the most effective treatment and is usually considered. The prognosis is generally excellent with appropriate treatment, since these tumors are mostly benign

Who gets Subungual Glomus Tumor? (Age and Sex Distribution)

• Subungual Glomus Tumors are very rare soft tissue tumors. It may affect individuals of any age, though it is frequently observed in young adults
• Tumors that form under the nail beds (subungual) are more common in females than males, even though both genders are affected
• All racial and ethnic groups may be affected and no preference is noted

What are the Risk Factors for Subungual Glomus Tumor? (Predisposing Factors)

Currently, the specific risk factors that contribute to Subungual Glomus Tumor development are unknown.

• A positive family history is seen when multiple lesions are present; in such cases, there is an autosomal dominant pattern of inheritance noted
• Neurofibromatosis type 1 (a genetic disorder) association is noted, typically when more than one finger or toe is involved

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Subungual Glomus Tumor? (Etiology)

The exact cause and mechanism of formation Subungual Glomus Tumor is unknown.

• In general, glomus tumors are observed to have a variety of mutations
• Inherited tumors show gene mutations; the glomulin gene in chromosome 1 is involved in such cases
• Multiple tumors are known to be inherited in an autosomal dominant manner

Autosomal dominant: Autosomal dominant conditions are traits or disorders that are present when only one copy of the mutation is inherited on a non-sex chromosome. In these types of conditions, the individual has one normal copy and one mutant copy of the gene. The abnormal gene dominates, masking the effects of the correctly function gene. If an individual has an autosomal dominant condition, the chance of passing the abnormal gene on to their offspring is 50%. Children, who do not inherit the abnormal gene, will not develop the condition or pass it on to their offspring.

What are the Signs and Symptoms of Subungual Glomus Tumor?

The following are the signs and symptoms of Subungual Glomus Tumors:

• A vast majority of glomus tumors are single; although in 1 in 10 individuals, multiple tumors may be present. Solitary tumors are often found in slightly older adults than multiple tumors (which is found in younger adults)
• On the finger nail or toenail, the tumor may appear as a very painful, raised swelling beneath the nail. The pain may increase on touch or on exposure to cold
• The size of the lesion is usually 1 cm or less
• There may be an underlying bluish skin discoloration (seen in 40% of the cases)
• The nail may be deformed (in about 50% of the cases)
• Multiple digits may be affected, if the presence of neurofibromatosis type 1 is noted

How is Subungual Glomus Tumor Diagnosed?

A diagnosis of Subungual Glomus Tumor may include the following:

• A thorough physical exam and complete evaluation of medical history
• The following classical triad of symptoms may be noted for subungual tumors which may be indicative:
  • Severe pain
  • Point tenderness
  • Cold sensitivity
• Hildreth’s test: The limb with the tumor is elevated to drain blood away from the site of the tumor. After elevation, a tourniquet is tied and subsequently, the tumor is touched. The pain upon touch should be significantly reduced. But when the tourniquet is removed, the pain on touch suddenly increases
• Love’s pin test: Individuals should experience severe pain and subsequent decrease in pain, when the skin on top of the tumor is pushed using a fine object, such as a paper-clip, a pinhead, a toothpick, or a ball-point pen tip
• Tissue biopsy of tumor specimen:
  • A biopsy of the tumor is performed and sent to a laboratory for a pathological examination. A pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis. Examination of the biopsy under a microscope by a pathologist is considered to be gold standard in arriving at a conclusive diagnosis
  • Biopsy specimens are studied initially using Hematoxylin and Eosin staining. The pathologist then decides on additional studies depending on the clinical situation
  • Sometimes, the pathologist may perform special studies, which may include immunohistochemical stains, molecular testing, and very rarely, electron microscopic studies, to assist in the diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Subungual Glomus Tumor?

Generally, Subungual Glomus Tumors are not associated with any serious complications. However, in some cases, the following may be noted:

• Severe pain from the lesion
• The tumor can recur after its surgical removal

How is Subungual Glomus Tumor Treated?

The treatment of Subungual Glomus Tumor may involve the following measures:

• The healthcare provider may recommend a ‘wait and watch’ approach for small, asymptomatic tumors
• Simple excision and complete removal of the tumor: It is the most effective treatment available for benign tumors
• Multiple tumors may be treated through any of the following means:
  • Laser therapy
  • Injection of hypertonic saline
  • Sclerotherapy
• Generally, medical therapy (treatment using medications) is not effective for treating the tumors
• Follow-up care with regular screening and check-ups are important

How can Subungual Glomus Tumor be Prevented?

Currently, there are no effective preventative methods available for Subungual Glomus Tumor. Avoiding exposure to severe cold may reduce aggravation of the signs and symptoms.

What is the Prognosis of Subungual Glomus Tumor? (Outcomes/Resolutions)

• With appropriate treatment, the prognosis of Subungual Glomus Tumor is typically excellent. since most tumors are benign in nature
• Following a simple excision and tumor removal, the pain and accompanying symptoms are known to subside

Additional and Relevant Useful Information for Subungual Glomus Tumor:

Please visit our Cancer & Benign Tumor Health Center for more physician-approved health information:

http://www.dovemed.com/diseases-conditions/cancer/