RESUMEN
BACKGROUND Glomus tumors are rare, benign, soft-tissue lesions, usually occurring in the hand, but they can occur in other regions of the body, such as the thigh. Most of the time, extradigital glomus tumors are difficult to diagnose, and symptoms can persist for a long time. The usual clinical presentations consist of pain, tenderness at the site of the tumor, and hypersensitivity to cold. CASE REPORT We report a case of a GT of the proximal thigh in a 39-year-old man with left thigh pain without palpable mass for several years, without clear diagnosis. He had pain and hyperesthesia exacerbated by running. The patient was diagnosed initially by ultrasound imaging, which revealed a round, solid, hypoechoic, homogeneous mass in the left upper thigh. Magnetic resonance imaging (MRI) with contrast showed a well-defined intramuscular lesion in the tensor fascia lata. A percutaneous biopsy was done through ultrasound guidance, followed by excisional biopsy and immediate pain relief. CONCLUSIONS Glomus tumors of the thigh are a rare neoplasm, especially in the proximal thigh; they are difficult to diagnose and are associated with morbidity. Diagnosis can be made through a systematic approach and simple investigation, such as via ultrasonography. A percutaneous biopsy can help in drawing up a management plan, and malignancy must be considered if the lesion is suspicious. Symptoms can persist in case of incomplete resection or unrecognized synchronous satellite lesions; thus, symptomatic neuroma should be considered.