Extradigital Glomus Tumor of the Forearm Identified During Neuromuscular Ultrasound: A Case Report

Abstract

Glomus tumors are rare benign soft tissue tumors that arise from the glomus body. They typically develop in the subungual region but may develop extradigitally anywhere, in the upper or lower limbs. Extradigital glomus tumors can be misdiagnosed for years because of their atypical position and presentation. Being aware of an extradigital glomus tumor is important because they can be encountered during imaging studies and may be the cause of the patient’s symptoms. This report presents a case of an extradigital glomus tumor, of the forearm, diagnosed during neuromuscular sonography, in a patient with chronic intractable neuropathic-like pain, along the medial side of the left forearm. Sonographic imaging of the nerves, muscles, and tendons did not reveal any abnormalities. However, meticulous imaging of all tissue layers detected a subcutaneous vascular nodule. Subsequent excision biopsy and histopathologic assessment revealed a glomus tumor. After surgery, the patient experienced dramatic relief of pain. This case report highlights the importance of careful sonographic examination of all the tissues, including skin and subcutaneous tissue layers, to avoid missing non-neuromuscular pathologies that impact patient’s management.