Glomus Tumor Causing Anterior Thigh Pain: A Case Report
A 65-year-old male patient was referred to our pain clinic due to pain in the left anterior thigh. The pain had begun 15 years earlier and had worsened following fine needle biopsy for the evaluation of a painful mass five years later. The nature of the pain was severe (score of 8 out of 10 on the visual analogue scale [VAS]) with constant dullness and paroxysmal lancinating pain. Clinical examination revealed severe tenderness at the biopsy site (VAS score 10 out of 10) and mild skin color change, loss of hair, decreased sweating, and static and dynamic allodynia and hyperalgesia in the left anterior thigh. The patient had been receiving treatment at another hospital where electromyogram, biopsy, and MRI results had been non-specific. Based on the clinical signs and symptoms, the patient had been diagnosed with complex regional pain syndrome (CRPS) type 1 and neuropathic pain. Previous treatments had included administration of non-steroidal anti-inflammatory drugs (NSAIDs), gabapentin, nortriptyline, opioids, and also several nerve blocks with little success. After arriving at our hospital, the patient received diverse interventional therapies during the next three months without significant results. Selective transforaminal epidural block (L1, L2 levels) and sympathetic ganglion block (L2 level) were effective in reducing pain 30% to 50% for only a day or two. Pulsed radiofrequency treatment of the L1 dorsal root ganglion also showed limited results. Although intravenous infusion of ketamine reduced pain for five days, the pain relief was only felt in the anterior thigh, while the tenderness in the biopsy site was not reduced.\nFurther examination with ultrasonography at the biopsy site confirmed a round 0.8 × 0.6 cm2 sized hypoechoic cyst in the subcutaneous fat tissue (). The patient first received injection of 3 ml of 0.75% levobupivacaine around the cyst under ultrasonography guidance, but this did not provide any pain relief. One week later, 2 ml of 0.75% levobupivacaine was injected directly into the cyst. Although the patient complained of severe pain during penetration of the cyst, the pain was then almost completely reduced for 24 hours. Tenderness on the biopsy site was also reduced to a VAS score of 5 out of 10 (from 10 out of 10). The patient was transferred to the surgery department and was diagnosed with glomus tumor following excisional biopsy (). The pain was immediately reduced postoperatively and the patient has been pain free for six months.