Glomus Tumor of the Finger

A glomus tumor is a rare, benign tumor that arises from the pericytes. These tumors involve the glomus body which is very vascular and a temperature regulator. This structure regulate peripheral blood flow to the digits. Glomus tumors occur more in females. Approximately 50% of glomus tumors occur in the fingertip, while the other 50% occur in the subungual area (under the nail).

The tumor contains arteriovenous communications. There will be a painful, bluish mass located under the nail bed. The patient’s symptoms will have a triad of characteristics:

· Pinpoint pain

· Pinpoint tenderness

· Cold intolerance

The patient may think it is a hematoma or blood under the nail and cover the lesion with nail polish. Diagnosis is usually delayed and the patient may be seen by a number of different physicians that are unable to diagnose the condition. Placing the digit in ice water can recreate symptoms in 60 seconds.

The tumor can erode the distal phalanx. Radiographs may be normal or show pressure erosion. There will be an intense bright signal in T-2 MRI. Treatment in the form of a marginal excision is typically done. Reoccurrence of the tumor is rare. This is an important topic to be familiar with, as it is usually an exam question.