RT Journal Article SR Electronic T1 Recurrent Optic Neuritis and Perineuritis Followed by an Unexpected Discovery JF Neurology - Neuroimmunology Neuroinflammation JO Neurol Neuroimmunol Neuroinflamm FD Lippincott Williams & Wilkins SP e200051 DO 10.1212/NXI.0000000000200051 VO 10 IS 1 A1 Daniela A. Pimentel Maldonado A1 Robert Lisak A1 Steven Galetta A1 Laura Balcer A1 Thomas Varkey A1 Andrew Goodman A1 Jennifer Graves A1 Michael Racke A1 Scott S. Zamvil A1 Scott Newsome A1 Elliot M. Frohman A1 Teresa C. Frohman YR 2023 UL http://nn.neurology.org/content/10/1/e200051.abstract AB We describe a woman with a history of relapsing acute optic neuritis and perineuritis. Testing failed to confirm a specific diagnosis; hence, she was diagnosed with seronegative neuromyelitis optica spectrum disorder and treated with the immunotherapy rituximab, later in conjunction with mycophenolate mofetil. She achieved a durable remission for 9 years until she presented with paresthesia affecting her left fifth digit, right proximal thigh, and left foot, while also reporting a 25-pound weight loss over the prior 3 months. New imaging demonstrated a longitudinally extensive and enhancing optic nerve, in conjunction with multifocal enhancing lesions within the spinal cord, in a skip-like distribution. The differential diagnosis is discussed.ACE=angiotensin-converting enzyme; anti-AQP4=aquaporin-4 antibody; BNS=Bing-Neel syndrome; BTK=Bruton tyrosine kinase; CBA=cell-based assay; CLL=chronic lymphocytic lymphoma; ED=emergency department; MMF=mycophenolate mofetil; MOG=myelin oligodendrocyte glycoprotein; MOGAD=MOG antibody disease; NMOSD=neuromyelitis optica spectrum disorder; ON=optic neuritis; RBC=red blood cell; VA=visual acuity; WBC=white blood cell; WM=Waldenstrom macroglobulinemia