Visual loss due to progressive multifocal leukoencephalopathy in a congenital immunodeficiency disorder.

A 20-year-old man with WiskottAldrich syndrome (WAS) initially developed a mild visual disturbance that progressed to blindness, increasing neurological deficits, and death within 4 months. Wiskott-Aldrich syndrome is an X-linked immunodeficiency disorder characterized by thrombocytopenia, eczema, and susceptibility to infection. This case illustrates the difficulties in reaching the final diagnosis of progressive multifocal leukoencephalopathy (PML) in this individual and its unusual histopathologic features.