A Glomus tumour is a rare, and harmless soft tissue growth. The glomus body is a normal part of the dermal layer of the skin and is thought to aid in temperature regulation. When exposed to cold temperatures, the glomus body moves blood away from the skin’s surface to reduce heat loss. While they are located all over the body, glomus bodies are found in higher concentrations in the fingers and toes. Abnormal growth of a glomus body results a Glomus tumour.

Glomus tumours usually occur in people 20 to 50 years of age but are more frequent in young adults. They are more common in women and 70% occur in the hand, mostly underneath the nail bed. Most of the nodules are solitary but they can occur in clusters. Glomus tumours represent 1 to 5% of all soft tissue tumours in the hand and fingers.

What causes Glomus tumour?

The cause of Glomus tumours is unknown but they are thought to have a hereditary link.

What are the symptoms of Glomus tumours?

Glomus tumours usually present with pain in the finger – under or around the nailbed. They are rarely visible and therefore the diagnosis and treatment are often delayed. There may be subtle blueish discolouration under the nail. Infrequently a small, firm, reddish-blue bump underneath the fingernail can be seen. These lesions are usually quite small, less than 7mm in diameter. They can be extremely painful, are sensitive to temperature change, and very tender with direct pressure. The pain is often worse at night and can be relieved by applying a tourniquet. The mass can cause irregular growth of the nail plate.

How are Glomus tumours diagnosed?

These tumours can often be diagnosed with high resolution ultrasound. If an ultrasound does not demonstrate the mass, an MRI may be required. Gadolinium contrast is often used with MRI to identify tiny glomus tumours as they are highly vascular. X-rays are usually normal but there can be subtle indentation of the terminal phalanx if the mass has been present for a long time. This is caused by pressure on the bone over time.

How are Glomus tumours treated?

The treatment involves a minor day surgery procedure where the nail plate is removed, a small incision made in the nail bed (the soft part under the hard nail plate) and the tumour removed. The nailbed is then repaired with several microsurgical stitches. The nail plate is put back on to protect the nailbed while it heals. The nail plate will fall off but a new one will grow. The rate of the tumour recurring is approximately 5%.