The association of progressive multifocal leukoencephalopathy and sarcoidosis.

A 59-year-old woman had a right homonymous hemianopsia, memory impairment for five months, a nonenhancing area in the left parieto-occipital region on CT scan, and bilateral reticulonodular infiltrates on chest x-ray film. Lung biopsy findings were consistent with sarcoidosis, a clinical diagnosis of CNS sarcoidosis made, and prednisone therapy begun. She deteriorated neurologically and died. At autopsy characteristic histologic and electron microscopic features of progressive multifocal leukoencephalopathy (PML) were found. We conclude that this and other cases demonstrate an association of PML and sarcoidosis and that steroid treatment is not a precondition. We also suggest an aggressive diagnostic approach in evaluating sarcoidosis with atypical neurologic deficits.