Lyme neuroborreliosis manifesting as an intracranial mass lesion.

Lyme neuroborreliosis is one of the chronic manifestations of Lyme disease and is caused by the neurotropic spirochete, Borrelia burgdorferi. Two of the three stages of Lyme disease potentially involve the central nervous system: a second stage that may manifest as meningitis, cranial neuritis, or radiculoneuritis; and a third stage, or chronic neuroborreliosis, with parenchymal involvement. The tertiary stage may mimic many conditions, including multiple sclerosis, polyneuropathy, viral encephalitis, brain tumor, vasculitis, encephalopathy, psychiatric illness, and myelopathy. We report a 10-year-old child with signs, symptoms, and radiological manifestations of intracranial mass lesions, without previously recognized manifestations of Lyme disease. This proved to be Lyme neuroborreliosis, documented by histological and serological examination, which responded well to antibiotic therapy. The need to establish a tissue diagnosis of intracranial mass lesions is emphasized, and the utility of a computed tomographic-guided stereotactic system for this purpose is discussed.