The value of diagnostic ultrasonography in the assessment of a glomus tumor of the subcutaneous layer of the forearm mimicking a hemangioma: a case report

INTRODUCTION A glomus tumor is a rare, benign tumor with atypical clinical symptoms. Because of its small size, it is difficult to diagnose and treat early; therefore, it leads to poor quality of life. Glomus tumors are known to commonly affect the hand and rarely manifest in other areas. Because they simulate neuromas, hemangiomas, and neurofibromatosis, the differential diagnosis is difficult. We performed marginal resection of a solitary forearm mass previously suspected to be a hemangioma or glomus tumor on the basis of ultrasound findings and histologically diagnosed to be a glomus tumor afterward. We report this case to demonstrate the good prognosis of the procedure we used, and we review the relevant literature. CASE PRESENTATION A 68-year-old Asian man without a particular medical history visited our hospital with a mass with focal tenderness in his left distal forearm that had developed 8 years earlier. The tumor was observed with suspicion of being a hemangioma or glomus tumor based on the location, clinical symptoms, and ultrasound findings taken into consideration together. The biopsy results led us to conclude that the lesion was a glomus tumor. CONCLUSIONS A glomus tumor located in the forearm is very rare. It is often clinically overlooked and is likely to be misdiagnosed as another disease. The patient's quality of life deteriorates, and, though the disease is rare, it has serious sequelae. Therefore, a quick diagnosis and appropriate treatment must be conducted early. If a mass occurs with serious pain in subcutaneous soft tissue of not the hands but the limbs, it is important to conduct examinations with suspicion of a glomus tumor. Ultrasonography performed quickly may be useful for making the differential diagnosis.