Extradigital Glomus Tumor Mimics an Intrinsic Nerve Tumor in a Trauma Patient: Case Report and Literature Review

Abstract

Glomus tumors are rare, painful, and usually benign neoplasms that typically occur at the subungual aspect of digits. Rarely, glomus tumors may arise in other areas of the body. We present a case of an extradigital glomus tumor on a forearm with prior trauma that presented with symptoms of an isolated peripheral neuropathy. Our review of literature reveals how upper or lower extremity glomus tumors can mimic neuropathies secondary to intrinsic nerve tumors (schwannoma, neurofibroma, or neuroma), radiculopathies, or manifestations of a complex regional pain syndrome (CRPS). We emphasize the need to consider a broad differential diagnosis that includes glomus tumor when evaluating patients with painful dermal masses producing peripheral neuropathy or radiculopathy signs owing to the infiltrative growth pattern into or mass effect exerted on nearby nerves.

Keywords: extradigital glomus tumor; nerve tumor; peripheral neuropathy; trauma; traumatic neuroma.

Figure 1. Plain radiograph image of left forearm shows 1.6 cm ovoid density within the lateral soft tissues.

Figure 2. MRI of left forearm, axial views. A: T1-weighted image without contrast that shows low-intensity well-circumscribed mass; B: T1-weighted image with contrast that shows strong enhancement of mass; C: T2-weighted image that shows hyperintense mass.

Figure 3. MRI of left forearm, sagittal view. T1-weighted image with contrast shows contrast-enhancing mass compressing the superficial branch of the radial nerve and associated vascular bundle.

Figure 4. Dense aggregates of glomus cells with characteristic round cells with bland round nuclei and interspersed small hyalinized vessels (H&E, 100x).

H&E: hematoxylin and eosin

Figure 5. Constituent cells are diffusely positive for calponin (IHC, 100x).

IHC: immunohistochemistry