We report a 62-year-old man with a relapsingremitting phenotype characteristic of early adulthood multiple sclerosis (MS). Onset with sequential, but rapidly remitting episodes of optic neuritis, transverse myelitis, and a brainstem syndrome followed autologous stem cell transplant (SCT) for plasma cell leukemia. This occurrence in a compound heterozygote for 2 MS-associated class II major histocompatibility haplotypes further implicates immune dysregulation in the etiopathogenesis of MS.Case report. A 62-year-old northern European man, without previous neurologic dysfunction, presented with weight loss, malaise, and thoracic back pain. Investigations revealed plasma cells in the peripheral blood, an immunoglobulin G (IgG) paraprotein of 50.7 g/L Ϫ1 with associated immunoparesis, and  2 microglobulin of 85.9 mg/ L Ϫ1 . Serum calcium was 3.1 mmol and there were lytic lesions and associated collapse of multiple thoracic vertebrae. Stage III plasma cell leukemia was diagnosed. He underwent 5 cycles of cytarabine/thalidomide/danarubicin chemotherapy and, 5 months after diagnosis, an autologous SCT with reinfusion of CD34ϩ stem cells following marrow ablation with melphalan. Within 6 months, he was in remission with an undetectable paraprotein and normal blood indices.Eight months following SCT, he developed isolated right retroorbital pain with central visual loss reaching a nadir at 1 week. A relative afferent papillary defect, an acuity of 6/9 (6/4.4 left), reduced color vision (Ishihara 6/17), and neurophysiologic data supported a clinical diagnosis of optic neuritis (figure, A and B). No significant white matter abnormalities were evident outside the affected optic nerve (figure, C). A full recovery ensued without treatment.Nine months following SCT, he developed a band of burning midthoracic discomfort that evolved over 1 week to include dysesthesia and allodynia below the level. Two weeks later, symptoms had fully resolved.Ten months after SCT, his gait became unsteady and his hands clumsy over 4 days followed by vertigo, diplopia, and oscillopsia. He became unable to mobilize safely. Examination revealed limited abduction of the left eye, degraded horizontal pursuit and hypometric saccades, gait ataxia, and decomposition of left arm movement. MRI showed new high T2 signal lesions in the left pons and cerebellar peduncle (figure, D). Blood indices were normal and no paraprotein detectable. CSF was acellular with a normal IgG:albumin ratio (0.12) and no oligoclonal bands detectable by immunofixation. Prior exposure to Epstein-Barr virus was indicated by the detection of IgG against Epstein-Barr virus-capsid antigen preand post-SCT. No treatment was given. By day 5, he mobilized with assistance, and in 2 weeks he had recovered. Tissue typing revealed he was a HLA-DRB1*15/HLA-DRB1*17 heterozygote.
Discussion.Remitting episodes of optic neuritis, probable transverse myelitis, and a brainstem syndrome occurring sequentially over 4 months allow the diagnosis of relapsing-remitting MS on clinical criteria. The absenc...