Neuroborreliosis with progression from pseudotumor cerebri to aseptic meningitis.

We report a patient with an initial diagnosis of Lyme-associated pseudotumor cerebri who developed cerebrospinal fluid pleocytosis consistent with Lyme meningitis. The case illustrates the importance of considering neuroborreliosis in the differential diagnosis of pseudotumor cerebri and describes the evolution of cerebrospinal fluid findings in this condition.