A rare neurological complication of Waldenstrom's Macroglobulinemia.

Bilateral and simultaneous facial nerve palsy (FNP) is a rare clinical condition occurring in 0.3-2.0% of facial palsy cases and is typically a manifestation of an underlying systemic disease. We here describe a case of a 67-year-old Hispanic man with a known history of Waldenstrom's Macroglobulinemia (WM) who presented to the clinic with a sub-acute onset of bilateral facial weakness. No alternate etiology for the facial weakness was identified after a thorough diagnostic approach. WM is a rare hematological condition due to low-grade B cell lymphoma, where lymphoplasmacytoid cells infiltrate different tissues and secrete monoclonal IgM. Peripheral neuropathy develops in 15-30% of the cases, being usually a chronic, progressive, symmetric, predominantly distal polyneuropathy. Facial nerve impairment is unusual; however, it could be caused by anoxic damage as a result of an increased blood viscosity from IgM monoclonal gammopathy, direct nerve infiltration of tumorous cells and an antibody (anti-MAG) mediated demyelinating process. Treatment is directed to the established mechanism for neural injury. This report highlights a rare condition (WM) with a rare complication (bilateral facial nerve palsy) and illustrates the broad differential comprised by this presenting complaint.