Progressive Multifocal Leukoencephalopathy With Occult Waldenström Macroglobulinemia

A 57-year-old, right-handed, whitemale was in his usual state of good health when he noticed a tremor in his right hand. He was experiencing difficulty with fine motor tasks, including writing and shaving, and was diagnosed with carpal tunnel syndrome. Because of symptom progression, a magnetic resonance imaging (MRI) scan of the brain was performed and revealed a mild T1-confluent, nonen-hancing, white-matter lesion in the right temporal cortex and in the posterior frontal left cortical region. It was hypothesized that the patient had experienced a stroke.However, during the next 3months, the patient noticed that his right leg began to contract and became considerablyweaker, affecting his gait.Onemonth later, he developed dysarthria and lost the ability to walk. A second MRI of the brain revealed progression of the previous abnormality. Lumbar puncture revealed three nucleated cells, a glucose level of 62 mg/dL, a protein level of 35 mg/dL, an albumin index of 9.8 with an increased immu