Glomus tumors are benign, but painful, growths originating from glomus bodies.1 These growths are rare, comprising just 1% of tumors arising in the hand2,3 and occur slightly more often in women than in men.2 In addition, only 10% or fewer glomus tumors are found in the volar pulp of digits.1,3 Hallmark symptoms of a glomus tumor include hypersensitivity to cold, heightened pin prick sensitivity, and paroxysmal pain.2,4–6
We report a case of a glomus tumor arising in an atypical location.
We report a 72-year-old, right-handed man who presented with pain in the left middle finger, localized to the tip, for a duration of 2 years. He had seen a primary care doctor, with no definitive diagnosis. The tip was excessively sensitive to touch, and his pain increased at night. The distal pulp of the long finger was tender, with no palpable mass. He reported that he could not recall any distinct trauma to finger. He is a retired vet and no longer smokes, although he did in the past.
The patient has a history of throat cancer, prostate cancer, renal cancer, myotonic dystrophy type II, gastroesophageal reflux disease, obstructive sleep apnea, osteoarthritis, and chronic back pain. He is allergic to penicillin and sulfa drugs.
The differential diagnosis at the time of examination included glomus tumor, giant cell tumor, ganglion cyst, epidermal inclusion cyst, liposarcoma, neurofibroma, and myxoma.
X-ray and magnetic resonance imaging (MRI) studies were done for the left hand. No bony lesions were identified by radiographic studies. An MRI of the left hand showed a round 7.0 × 4.0 × 6.0-mm T2 hyperintense, T1 hypointense soft tissue lesion along the volar ulnar aspect of the distal third digit, deep to the distal phalanx (Fig. 1). The osseous structures were in anatomic alignment. Muscle bulk and signal were preserved. The visualized flexor and extensor tendons were intact.
Surgical intervention was performed (Fig. 2). An incision was made in the mid-axial plane. The mass was well circumscribed and removed with blunt dissection and sent to pathology. It was a tan-yellow, soft tissue nodule of 0.8 cm in diameter and had no stalk or adherences to a joint. Pathology confirmed from hematoxylin and eosin-, actin-, CD31-, CD34-, ETS-related gene-, and vimentin-stained slides showed that the excised mass was a glomus tumor. The glomus tumor cells were positive for actin, CD34, and vimentin. This, combined with hematoxylin and eosin morphology, supported the diagnosis of glomus tumor. The patient’s symptoms improved on removal of tumor, and he healed without complication. This article does not contain any studies with human or animal subjects. Informed consent was obtained from the patient.
Glomus bodies are contractile tissue and are primarily responsible for local temperature and blood pressure modulation, and they accomplish this by controlling blood flow through microvasculature.3 These neuromyoarterial receptors are concentrated in the fingers and toes, especially near the tips and under the nails.1,2,6 Thus, finding the glomus tumor in the pulp of the distal end of the patient’s finger, as presented here instead of underneath the nail bed, is unusual.
Although the precise cause of glomus tumors is unknown,2 they have been linked to the monogenic disorder neurofibromatosis 1 of the NF1 phenotype.7 This disorder increases the likelihood that tumors are developed. The tumors likely originate in modified smooth muscle cells of the glomus body network, due to biallelic deactivation of the NF1 gene.7
Typically, glomus tumors manifest with 3 symptoms: hypersensitivity to cold, heightened pinprick sensitivity, and paroxysmal pain.2,4–6 In addition to ruling out other possible causes of pain, correctly diagnosing a glomus tumor should involve the positive result on 3 tests: Love’s pin test, a cold sensitivity test, and Hildreth’s test.5 Love’s pin test utilizes the head of a pin pressed against the site of the pain to identify the focal point. For Hildreth’s test, the patient’s lesion must be first stimulated to provoke severe pain. After that, a tourniquet is applied, and Love’s pin test is repeated; the absence of pain from the pin after applying the tourniquet indicates a positive result for Hildreth’s test. A positive result on the cold sensitivity test manifests as an increase in pain due to the cold. The mechanism for this may depend on the vasodilation of the Souquet–Hoyer arteriovenous channels, which dilate in response to cold to prevent excessive digit heat loss.5
In addition, imaging studies such as ultrasound and MRI can be valuable tools for ruling out possibilities, visualizing, and diagnosing glomus tumors. In this case, MRI imaging studies and x-rays revealed the mass to be in the distal pulp of the patient’s middle finger. Being an atypical location, this made diagnosis difficult. However, surgical excision was still the best course of action, given the 2-year duration of the symptoms and information revealed from MRI.
Complete removal of the mass is necessary to prevent the glomus tumor from growing and troubling the patient again.3,8 Recurrence rate can be anywhere from 5% to 50%.3 Typically, the mass is extracted transungually by removal of the nail plate and by making an incision along the nail bed.3 An alternative method is a lateral incision along the dorsal side of the distal phalanx, which grants access to the mass without damaging the nail bed.3 This allows excision with less damage to the nail bed, but it is associated with higher recurrence, due to a limited perspective and greater likelihood of incomplete removal.3 However, neither of these approaches were employed, as the mass was located in the distal volar aspect of the digit. The nail bed was not disrupted, as the incision was made along the mid-axial plane for blunt excision of the mass.
We report the case of a glomus tumor arising in the unusual location of the volar pulp of a finger, with typical symptoms of long-term pain and sensitivity to touch. Glomus tumors are difficult to diagnose, without specific tests, considering the vague symptoms. The deep and unusual location of the mass presented here made diagnosis of the identity of the mass equivocal. However, the presence of localized pain in the fingertip was a reason to include glomus tumor in the differential diagnosis, to limit delay of treatment.
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