Sir,

This was the case of a 32-year-old female patient who presented with pain in her left middle finger that had persisted for ten years. For that pain, she had received multiple treatments, infiltrations, and antibiotics. A month prior, she suffered trauma to the same finger, which exacerbated the pain.

Her family history included diabetes mellitus, cancer, and high blood pressure.

Her personal history included an allergy to penicillin, pork, seafood, and beetroot. Her surgical history included cholecystectomy; polycystic ovaries; insulin resistance syndrome treated with metformin 750 mg/day.

On physical examination, localized onychopathy was observed in the left middle finger, characterized by reddish discoloration and distal nail depression (Fig. 1a). Dermoscopy revealed erythema and telangiectasia (Fig. 1b). The rest of the physical examination showed pseudoacanthosis nigricans and melanocytic nevi. Based on these findings, a clinical diagnosis of a glomus tumor in the left middle finger was established, and the patient underwent surgery.

Figure 1: (a) The nail shows reddish discoloration and distal nail depression. (b) Dermoscopy reveals erythema and telangiectasia.

During the procedure, after asepsis and antisepsis, an interdigital block was administered using 2% lidocaine. A tourniquet was applied. The nail plate was avulsed and the nail bed was lifted. A lesion consistent with a glomus tumor was identified, and complete excision was performed (Fig. 2). Hemostasis was verified, and the nail bed was repositioned using 5-0 Vicryl. The tourniquet was removed, and a wound dressing was applied. The excised tissue was sent for microscopic histopathological examination.

Figure 2: After avulsion of the nail plate and elevation of the nail bed, a lesion consistent with a glomus tumor is identified.

Histopathology revealed subungual lesion tissue with fibrosis and nests of small cells with hyperchromatic nuclei, scant cytoplasm, and glomus cells (Fig. 3).

Figure 3: Subungual lesion with fibrosis and nests of small cells with hyperchromatic nuclei, scant cytoplasm, and glomus cells.

A glomus tumor is a benign vascular neoplasm arising from neurovascular structures known as glomus bodies. It is characterized by a triad of cold sensitivity, stabbing pain, and a positive Love’s test [1].

Among soft tissue tumors of the hand, glomus tumors represent approx. 1–5%, occurring more frequently in women between the ages of 20 and 50 [1,5].

It usually presents as a painful, subungual nodule, and symptoms may persist for years [7]. Several clinical tests support the diagnosis, including [1,2,5]:

For diagnosis, high-frequency Doppler ultrasound may be employed. It allows the detection of hypervascular lesions smaller than 4 mm, even in cases where the tumor is invisible or palpable. Likewise, MRI enables the identification of hypervascular lesions under 4 mm, even when the tumor is not clinically evident. It also delineates lesion margins, aiding in surgical planning. MRI offers an approximate sensitivity of 94% and specificity of 80%. The lesions typically appear hypointense on T1-weighted images and hyperintense on T2-weighted sequences [6].

Glomus tumors may, although uncommonly, present as multiple lesions affecting several digits. Through MRI, subungual masses may be accurately identified, allowing for timely surgical treatment and appropriate follow-up. This underscores the importance of comprehensive imaging evaluation in clinically atypical or persistent cases and highlights the need to consider multifocal lesions [5].

Histologically, these tumors are composed of proliferating glomus cells located around blood vessels. Three main variants are recognized: solid glomus tumor, glomangioma, and glomangiomyoma [1,5]. Immunohistochemical staining shows glomus cells positive for smooth muscle actin and type IV collagen. In rare cases, malignant variants such as glomangiosarcoma may be observed [1,5].

It is worth noting that some subungual glomus tumors may cause median canaliform nail dystrophy of Heller. This results from pressure exerted by the tumor on the nail matrix, producing a central longitudinal depression with a characteristic “fir-tree” pattern along the nail plate. These clinical signs may help to guide diagnosis even when a palpable mass is absent [6].

There is documented evidence of a case in which, despite a negative Hildreth’s test, a positive Love’s test and MRI led to the identification of the tumor. This case illustrated the value of imaging studies even when clinical tests yield discordant results [6].

These tumors may be effectively managed through complete surgical excision. A conservative approach via a transungual route may be considered, offering benefits such as the preservation of the nail plate and prevention of deformities [2,3].

Glomus tumors may present as multiple lesions in patients with type 1 neurofibromatosis (NF1), with an early onset in up to 5% of cases. It is important to maintain clinical suspicion for painful, recurrent digital lesions, even though systematic screening is not currently recommended [4].

It should be emphasized that histopathological examination not only excludes possible malignant variants, yet also confirms the diagnosis and guides appropriate clinical management [7].

In conclusion, subungual glomus tumors may be challenging to diagnose due to their rarity and non-specific initial symptoms, despite their benign nature. Clinical suspicion, combined with imaging studies such as high-frequency Doppler ultrasound or MRI, allows for early diagnosis and effective surgical treatment. Considering this pathology in the differential diagnosis of nail pain improves both the functional and aesthetic outcomes for the patient.

REFERENCES

1.Milla Bello CE, Orozco Bustos MD, Nagore Ancona JF. [Subungual glomus tumor]. Cir Plást. 2020;30:48-51.

2.Lazo Vera J. [Subungual glomus tumor in the little finger and the use of ultrasound in its diagnosis:Case presentation]. Horiz Med (Lima). 2021;21:e1264.

3.Quinto González KL, Espinosa Gutiérrez A, Hernández Méndez Villamil E, Borjón Cisneros AE. [Subungual glomus tumor in the thumb and use of ultrasound in its diagnosis]. Acta Ortop Mex. 2023;37:368-71.

4.Navarro Sáez I, Chueca Rodríguez L, Ríos Blanco JJ, JordáCuevas E. [Multiple glomus tumor in a patient with type 1 neurofibromatosis]. Glosa Dermatológica. 2019;30:29-32.

5.Mathias R, Ramdas S, Varghese RG. Subungual glomus tumour. Our Dermatol Online. 2012;3:134-5.

6.Gupta M, Sharma V, Mahajan VK, Singh R. Subungual glomus tumor:An uncommon cause of median canaliform nail dystrophy of Heller. Our Dermatol Online. 2014;5:62-4.

7.Al Faker I, Marraha F, Gallouj S. Painful nail:What is your diagnosis?Our Dermatol Online. 2021;12:e73.