Is it Naughty or Nice?

Intravenous methylprednisolone (1 g daily) was administered for 7 days with significant improvement in visual function, and she was discharged on a prednisone taper. At 3 weeks, exam showed visual acuity of 20/25 OD, 20/40 OS, with mild disc swelling and a small paracentral scotoma OS. Given large multifocal ring-enhancing lesions and enhancing optic nerves on MRI, work-up was initiated to rule out neoplastic, infectious and inflammatory etiologies. The patient's young age, acute onset of symptoms, lack of prominent neurologic signs or symptoms (relative to the size of the lesions), normal CT chest/abdomen/pelvis, and normal CSF cytology made a neoplastic process unlikely. Normal white blood counts (blood and CSF), and the absence of systemic illness or immunocompromised state made an infectious etiology less likely. The presence of bilateral optic neuritis along with tumefactive-appearing MRI lesions raised suspicion for a demyelinating or inflammatory etiology. Because of atypical features, profound visual deterioration and lack of a unifying diagnosis, brain biopsy was performed. Neuropathology showed vast areas of confluent demyelination, marked histiocytic infiltrates, perivascular lymphocytic cuffs, and numerous Creutzfeldt cells - suggestive of acute fulminant MS (Marburg variant).2 Although our case shares similarities with acute disseminated encephalomyelitis (ADEM - eg, age, preceding viral illness, multifocal ring-enhancing lesions, bilateral optic neuritis), neuropathology did not show multifocal inflammation and demyelination centered around venous structures, which would be expected in ADEM. 2 Furthermore, the deep gray matter and spinal cord are commonly affected in ADEM. 2 She did not meet diagnostic criteria for traditional MS (despite similarities to tumefactive MS) because of the (so far) monophasic course and absence of prior neurologic symptoms. Most reported cases of the Marburg variant are rapidly progressive despite treatment, invariably leading to demise (with few exceptions) within weeks to months. 3 It would seem that our patient represents a relatively benign case of "fulminant" MS.