Mononeuritis multiplex as the first presentation of refractory sarcoidosis responsive to etanercept.

Background: Several disorders may present with mononeuritis multiplex and the etiological diagnosis can be challenging.

Case Presentation: We report a 42 year-old female who presented with severe lower limb neuropathic pain, asymmetric weakness and sensory impairment and was diagnosed with mononeuritis multiplex. Biopsy showed a granulomatous vasculitic process with eosinophils, scarce granulomata and axonal neuropathy and granulomatosis with poliangiitis was assumed. Steroids, cyclophosphamide, alemtuzumab, azathioprine, mycophenolate mofetil and rituximab were used, all with transient and insufficient response. Skin biopsy performed in a further exacerbation allowed sarcoidosis diagnosis. Infliximab and, later, adalimumab induced good clinical and laboratorial response, but neutralizing antibodies developed to both drugs, so etanercept was tried with good clinical response.

Conclusions: To the best of our knowledge, this is the first report of sarcoidosis successfully treated with etanercept. This drug may be considered in refractory sarcoidosis after other TNF-α inhibitors failure, having the advantage of not being associated with neutralizing antibodies development.