Persistent finger discomfort: Glomus tumor—a case report

Abstract

Glomus tumors are rare benign hamartomas, primarily small growths, found in the dermis or subcutaneous tissue, arising from modified glomus cells, which are distributed throughout the body, with a particularly high concentration in the subungual area of the fingers. This case reports a middle-aged man with persistent pain in the tip of his left ring finger for the past 5 years. With ideal imaging, the tumor was identified and surgically excised, and the patient is currently asymptomatic. Despite its presentation as a faint bluish-purple papule with the classic triad of cold hypersensitivity, paroxysmal pain, and point tenderness, it is often missed by clinicians and diagnosed late. With magnetic resonance imaging being the gold standard, the only resolution to pain relief is the complete excision of the tumor. Glomus tumors have been defined and estimated to be a few but significant part of hand tumors; however, in Africa, the prevalence is minimal and clinicians may be unaware of the presentation.

Introduction

Glomus tumor is a rare benign hamartoma arising from modified glomus cells, which are specialized smooth muscle cells functioning as chemoreceptors [1]. The glomus body serves as a source of thermoregulation via arteriovenous shunts [2]. Glomus bodies are distributed throughout the body, with a particularly high concentration in the subungual area of the fingers. Rarely found in other locations, such as the lungs, pancreas, stomach, genitourinary tract, and gastrointestinal tract, it is often misdiagnosed [1,3].

Glomus tumor was first described by Wood in 1812 [4] and later by Hoyer in 1877, with a full clinical description given by Masson in 1924 [5]. Glomus tumors are primarily small, benign growths found in the dermis or subcutaneous tissue of the extremities, with some cases presenting as solitary growths while others occur in multiple formations. While malignant occurrences are rare, they tend to involve large, deep-seated lesions exceeding 2 centimeters in size and often affect visceral organs. Additionally, giant intravenous glomus tumors have been reported [1]. This case report highlights the presentation and diagnostics of a glomus tumor.

The work has been reported in line with the SCARE criteria [6].

Case report

A 45-year-old male, of Maasai origin, presented at our outpatient clinic complaining of pain in the tip of his left ring finger persisting for the past 5 years, associated with on and off neck pain, with no history of preceding trauma and no skin discoloration. He localized the pain to a specific point near the distal phalanx tip and noted worsening discomfort upon exposure to the cold. Initially, he reported the pain to be mild but bearable, as it had not bothered his daily activities, and he did not seek any medical advice. He had noted that the pain kept worsening with time. He reported no similar complaints in his family. He had attended multiple health facilities including traditional healers, which were unable to assist his predicament. Lastly, misdiagnosed and treated for gout arthritis, he found no relief from the prescribed antipain management and considered elective disarticulation of his left finger's distal interphalangeal joint for pain relief, ultimately opting to seek care at our center.

Upon examination, he appeared well with no signs of systemic illness, lymphadenopathy, or finger clubbing, but exhibited sharp tenderness centrally at the nail of the left ring finger with features of swelling and no signs of inflammation. Applying pressure to the left ring finger using a pinhead resulted in intense localized pain (Love's pin test), and the pain was reduced by applying a tourniquet to induce transient ischemia (Hildreth's test). Applying cold water to the left ring finger induced pain (Cold test). His initial laboratory investigations revealed a normal leukocyte count of 4.7 × 10⁹/L, a hemoglobin of 15.3 g/dL, and a platelet count of 280 × 10⁹/L. He had a normal creatinine of 98 µmol/L and an elevated uric acid of 492.6 µmol/L (normal: 202.3-416.5). His rheumatoid factor was negative. An x-ray imaging revealed depressions on the dorsal aspect of the distal phalanx (Fig. 1). Magnetic resonance imaging of the left hand showed a well-defined isointense T1, hyperintense T2/STIR soft tissue mass in the nail bed measuring 0.3 cm × 0.3 cm × 0.5 cm in size. (Fig. 2), confirming the diagnosis of a glomus tumor.

Fig. 1.

X-ray of left ring finger shows depression on the dorsal aspect of the distal phalanx (yellow arrow) with no lesion or bone involvement visible.

Fig. 2.

Magnetic resonance imaging of the ring finger of the left hand shows a (A) well-defined isointense T1, and (B) hyperintense T2/STIR soft tissue mass in the nail bed (yellow arrow) measuring 0.3 cm × 0.3 cm × 0.5 cm in size.

Under local anesthesia and with a finger tourniquet, complete marginal excision and bone curettage were performed using surgical loops to ensure thorough tumor removal (Fig. 3), with no postoperative complications observed. The sample was sent to histopathology, which showed perivascular proliferation of homogenous round cells with round-to-ovoid nuclei arranged in multicellular layers around blood vessels (Fig. 4). On 2 weeks of follow-up, he reported that the pain had disappeared. On subsequent follow-up visits, the surgical site had healed and there was no pain reported after tumor removal. Telephone follow-up after 1 year, he reported no complaint. From then on, he has experienced complete symptom resolution with no recurrence during a 2-year follow-up.

Fig. 3.

(A) Under sterile conditions, complete marginal excision and bone curettage was performed to ensure thorough tumor removal. (B) Post excision showing the glomus tumor.

Fig. 4.

(A) x400, multiple vascular channels lined by endothelial cells and aggregates of round cells with darkly staining round to ovoid nuclei and eosinophilic cytoplasm. (B) x400, immunohistochemistry for SMA shows both cytoplasmic and membranous positivity.

Discussion

Our case presented classic features associated with glomus tumors of swelling at the subungual region associated with pain that worsened in the cold [7]. This tumor typically presents with cold hypersensitivity, pain, tenderness, and sometimes nail deformities or nail discoloration [8]. Glomus bodies are associated with temperature regulation by controlling microvascular blood flow [9]. Despite its presentation as a faint bluish-purple papule with the classic triad of cold hypersensitivity, paroxysmal pain, and point tenderness, it is often missed by clinicians and diagnosed late [1,2]. Subungual glomus tumors have been shown to have a higher incidence among female patients, while extradigital glomus tumors have not shown any gender predilection [5].

Glomus tumors are benign vascular neoplasms, accounting for ∼5% of all hand tumors and ∼2% of soft tissue tumors [10]. However, in the African context, glomus tumors account for <0.1% [4]. There have been 108 reported cases (including this case) of glomus tumors in Africa, with a male-to-female ratio of 1:1.4, and ∼70% occurring in the hands (Supplementary Table 1).

Glomus tumors arise from the contractile neuromyoarterial structure found in the reticular dermis layer, known as the glomus body. The glomus body consists of the afferent arteriole, anastomotic vessel, primary collecting vein, intraglomerular reticulum, and capsular portion [11]. Although the etiology of glomus tumors is unknown, theories propose a relationship to prior trauma. Patients typically deny a specific history of trauma, and it is usually difficult to completely rule it out as the starting point of this diagnosis. The patient had tested positive for the Love's pin test and the Hildreth's test, and from history, the patient had already reported sensitivity to cold temperatures.

The delay in diagnosis, in this case, was 5 years. During this period, the patient visited many health professionals without a definite diagnosis or management plan. Diagnostic delays can occur for several reasons: glomus tumors are often small, located deep in the fingertips, and are usually not palpable, making them difficult to diagnose; the pain may be mistaken for neuromuscular pain, chronic regional pain syndrome, gouty arthritis, etc. [12]; health professional may not be familiar with the classic triad of symptoms, as the diagnosis can be made up to 90% of cases [13]; the diagnostic imaging approach used may not guide the health professionals to the correct diagnosis.

Radiographs may show cortical thinning or erosive changes in the adjacent bone, while ultrasonography may demonstrate the size, site, and shape of the glomus tumor, this is heavily operator-dependent [14]. Computed tomography may show abnormalities or erosions of the distal phalanx but a dynamic computed tomography angiography may show hypervascularized tumor [15]. However, the patient underwent magnetic resonance imaging, the gold standard, which confirmed a glomus tumor. The appearance reveals a high-signal central dot surrounded by a zone of lower signal intensity. They are well-defined nodular lesions in the subungual region with T1-weighted images showing hypo-intense signal intensity, and T2-weighted images showing hyper-intense signal intensity. After gadolinium injection, T1-weighted images show homogenous contrast enhancement [16]. Some glomus tumors may have hypo-intense signal intensity in T2-weighted images and are better delineated with T2 fat suppression images with contrast [14].

The differentials include other painful tumors, such as mucous cysts, subungual exostosis, neuroma, hemangioma, angioleiomyoma, eccrine spiradenoma, osteochondroma, or gouty arthritis [14]. Some of the diagnoses can be differentiated based on the physical examination: mucous cysts present with a small, fluid-filled bump; subungual exostosis presents with visible nail deformity and swelling around the fingertip; neuromas are diagnosed by the Tinel's sign; hemangioma presents with a red, rubbery bump or flat patch on the finger; and osteochondroma presents with a firm, nonmobile mass. Radiographs are the primary diagnostic tools in cases with subungual exostosis and osteochondroma. An ultrasound may help to visualize pathology in cases with neuroma, hemangioma and angioleiomyoma. The challenge with MRI is that an angioleiomyoma may demonstrate a well-circumscribed mass with a slightly hyper-intense signal intensity on T2-weighted images [17,18]. Multiple glomus tumors should be carefully differentiated from cavernous hemangioma and blue rubber-bleb nevus syndrome, as they can be easily confused with one another [19].

Histologically, glomus tumors are usually well-circumscribed nodules comprised of uniform round cells with centrally located nuclei and well-defined cell borders. The cells are generally perivascular in arrangement. Glomus tumors tend to stain positively for smooth muscle actin, muscle-specific actin, calponin, h-caldesmon, and collagen type IV [2]. And stains negatively for Cytokeratin, CD31, and S100 [19].

Treatment is complete surgical excision of the tumor, as the patients usually report no symptoms postexcision [2]. However, with incomplete excision, there is a chance of recurrence [7]. The only resolution to pain relief is focused on the complete excision of the tumor, as anti-inflammatory therapy has shown no effect [20].

Conclusion

The few cases reported in Africa may highlight the failure of clinicians to diagnose glomus tumors. The delay in onset of symptoms and definitive treatment varies, but complete surgical excision of the tumor is curative. However, this case is a reminder for clinicians to be wary of glomus tumors, as they are curable but, left untreated, cause incapacitating pain for the patient.

Patient consent

Informed written consent was obtained from the patient for publication of this case report and all imaging studies.