Differential Dx includes subungual warts, Bowen’s disease
Clinical mimics of glomus tumors include neuromas, melanomas, Bowen’s disease, arthritis, gout, paronychia, causalgia, subungual exostosis, osteochondroma, and subungual warts. (The TABLE1,6-8 describes some of the more common mimics.)
In an analysis of 43 patients with glomus tumors, only 19% of referring practitioners and 49% of hospital-based practitioners correctly made the diagnosis.3
Suspect a glomus tumor? Perform these tests
Three clinical tests can aid in evaluating for glomus tumors.
- Love’s test involves applying pressure to the affected fingertip using the head of a pin or the end of a paperclip. The point of maximal tenderness locates the tumor.
- In Hildreth’s test, the physician applies a tourniquet to the digit and repeats the Love’s test. The test is considered suggestive of glomus tumor if the patient no longer experiences tenderness with pressure.
- The cold sensitivity test requires that the physician expose the finger to cold by, say, placing the finger in an ice bath. This exposure will elicit increased pain in a patient who has a glomus tumor.
The sensitivity and specificity of these tests, according to one study involving 18 patients, is as follows: Love’s test (100%, 78%); Hildreth’s test (77.4%, 100%); and the cold sensitivity test (100%, 100%).9 Clinical suspicion must be confirmed by histopathologic examination and the patient must be alerted to the risks of biopsy, which include permanent nail deformity.
In addition, imaging studies may aid in the diagnosis as well as determine the preoperative size and location of the tumor. Radiography may show bone erosion in certain cases, and it is useful in differentiating a glomus tumor from subungual exostosis.10 Magnetic resonance imaging and ultrasound imaging have also been used to identify glomus tumors and to aid in determining the method of excision.10,11
Surgical excision is the preferred approach
While there are reports of successful treatment with laser and sclerotherapy, surgical excision remains the accepted intervention to relieve pain and minimize recurrence.12,13 The optimal surgical approach, which depends on the location of the tumor,13,14 will minimize the risk of postsurgical nail deformity while allowing for complete tumor removal.
A biopsy for our patient
While the intent of our biopsy was diagnostic, it also proved to be therapeutic as our patient experienced complete resolution of her pain immediately after the procedure. Six months later, she remained asymptomatic and reported no nail deformity. We counseled her on the possibility that her symptoms might return and encouraged her to come back in for further care as needed.
Thomas M. Beachkofsky, MD, Wilford Hall Medical Center, Department of Dermatology, 2200 Bergquist Drive, Suite 1, Lackland AFB, TX 78236-9908; firstname.lastname@example.org