Glomus tumor: A rare differential diagnosis for subungual lesions

Abstract

Glomus tumors are rare, benign vascular hamartomas of the glomus apparatus with unknown etiology. They can arise from anywhere in the body. However, up to 90% of them are located in the subungual region of the fingers, as in the case of our patient. These tumors typically present with the classic triad of pain, cold sensitivity, and point tenderness. Characteristic US and MRI findings aid the clinical diagnosis; nevertheless, a histopathologic examination is confirmatory. There is a well-documented mean delay in diagnosis of around 7 years, due to the rarity, benignity, small size, and lack of proper knowledge about the condition. However, we reported a case with a delay in diagnosis that reached 40 years, which is much longer than what is documented in the literature. A high index of suspicion is required for early diagnosis and management of glomus tumors to relieve the patient's long-term suffering and prevent possible secondary nail deformities. The curative treatment of glomus tumor is complete surgical excision, which is crucial to prevent recurrence and relieve the patient's symptoms.

Keywords: Finger sensitivity; Glomus tumor; Painful nail; Subungual lesion.

Fig. 1

Comparison between the 2 middle fingers of (A) the right hand and (B) the left hand illustrates the swelling in the proximal nail fold and nail plate of the right one.

Fig. 2

Normal plain X-ray of the right hand.

Fig. 3

MRI appearance of the tumor: The mass has low signal intensity on T1 (A) and marked hyperintensity on T2 (B). The characteristic “central dot sign,” is visible on the STIR sequence (C, orange arrow).

Fig. 4

(A) Tumor consists of collars, nests, and groups of epithelioid cells (Black arrows) surrounding dilated and thick-walled blood vessels (Black arrowheads) embedded within fibrous stroma (H&E, 10x). (B) There are focal myxoid changes in the stroma (Red arrow) with mild mononuclear inflammatory infiltrate including mast cells (Red arrowheads) (H&E, 20x). (C) Tumor cells (Blue arrows) are uniform with indistinct borders, eosinophilic cytoplasm, round nuclei, and bland chromatin with minimal mitotic activity. No atypia, mitoses or necrosis were identified (H&E, 40x).

Fig. 5

The patient showed uneventful healing and nail growth at (A) 2 months, (B) 3 months, and (C) 9 months.