Definition
Also known as a glomangioma, this is a benign but exquisitely painful tumour that arises from the modified smooth muscles of the glomus body, which is a neuromyoarterial receptor that is sensitive to variations in temperature and regulates arteriolar flow.
Pathology
Two components are present: branching vascular channels separated by a connective tissue stroma that contains the second element, namely aggregates, nests and masses of the specialized glomus cells.
The lesions are usually less than 10mm in diameter and most are less than 3mm.
Clinical presentation
Symptoms have usually been present for years.
Pain may be associated with changes in temperature or gentle touch.
Extremely painful to palpation.
Can be found anywhere in skin but are most commonly found in the distal portion of the digits, especially under the fingernails.
When located under the skin they are slightly elevated, rounded, red-blue, firm nodules.
When located under the fingernails they appear as splinter haemorrhages.
Radiology
Shallow, well marginated erosion in the underlying bone, usually in the tuft of the terminal phalanx. Note that enchondromas are very rare here.
Treatment
Complete excision, with repair of the nailbed, is curative.