glomus tumor is a rare benign neoplasm that arises from the
neuroarterial structure called a glomus body, which accounts for 1 % to
5 % of soft-tissue tumors in the hand. The normal glomus body is
located in the stratum reticulare throughout the body, but is more
concentrated in the digits. They are believed to function in thermal
regulation. The normal glomus (glomus body) is an arteriovenous shunt that is composed of an afferent arteriole, an anastomotic vessel (Sucquet-Hoyer canal), a collecting vein, and a capsular portion. Histologic analysis shows vascular channels surrounded by irregularly arranged cuboidal cells. Nerves are found and may account for the pain. The tumor is surrounded by a fibrose capsule. A glomus tumor may be considered a hamartoma rather than a true tumor. The tumor is most commonly found on the distal extremities (75% occur in the hand) in the nail bed and subcutaneous tissue, especially at the tips of the first to fourth fingers
The average age at presentation is
from 30 to 50 years of age, although they can occur at any age. Because
the symptoms are not always specific and the physical examination is
frequently normal, the time from the onset of symptoms to the correct
diagnosis is usually long and sometimes several years.
The classical symptoms are temperature
sensitivity and local tenderness. Sometimes there is pain during the
night. However the symptoms vary. The smaller lesions are very
difficult to detect during physical examination.
The radiological findings can be
unremarkable. Larger lesions can cause bony erosions which can be
detected on the lateral X ray of the finger.
Ultrasound has proved to be very sensitive for the detection of glomus tumors.
The ultrasound characteristics are:
-Thickening of the soft tissues between the distal phalanx and the nail
-Sometimes a circumscribed hypoechoic mass is present
-Bony erosion of the distal phalanx
-Hypervascularity of the subungual tissues compared to the normal side
MRI also has proved to be sensitive
for the detection of glomus tumors, but ultrasound is much quicker and
cheaper. De ultrasound findings are highly pathognomonic. However
ultrasound is as always operator dependent
For more examples of glomus tumors and ultrasound see www.ultrasoundcases.info