ESRA19-0337 Macrodystrophia lipomatosa as cause of localized neuropathic pain

Background and aims Neuropathic pain is one of the most challenging conditions we face daily in pain clinic. We present a case of neuropathic pain due to overgrowth of the collateral nerve (median nerve branch) of the right third finger caused by macrodystrophia lipomatosis, a rare disease characterized by progressive proliferation of mesenchymal elements, mainly fibroadipose tissue. Methods A 32-year-old man underwent surgery to presumably remove an angiomyolipoma on the palmar side of the right hand third finger base. However, no angiomyolipoma was found, but instead an overgrown fatty third collateral nerve, with no possible surgical treatment besides decompression of the surrounding soft tissue. Six months later, patient complained of mild neuropathic pain (VAS 2) on the distal metacarpal area and third finger but severe pain under touch or pressure (VAS 8–9) with intense positive Tinel sign. Ultrasound only showed fat tissue around the nerve. After considering pharmacological treatment (patient reluctant to possible adverse effects) and capsaicin 8% patch, interventional treatment was our first choice, as one specific nerve was involved. We performed an ultrasound guided diagnostic block with local anaesthetic and corticosteroid on the proximal affected nerve, followed by a double bipolar pulsed radiofrequency on a second approach, 2 weeks apart. Results After 5 months follow up, continuous neuropathic pain had disappeared (VAS 0). Elicited pain from pressure lowered significantly (VAS 2–3). Conclusions Early treatment of neuropathic pain is essential to avoid chronification and central sensitization. Neuropathic pain due to specific nerve damage can be successfully treated with pulsed radio frequency.