False-negative cerebrospinal fluid cryptococcal antigen test due to small-colony variants of Cryptococcus neoformans meningitis in a patient with cystopleural shunt.

This is the first report of a small-colony variant Cryptococcus neoformans isolated from the cerebrospinal fluid of a patient with cystopleural shunt associated chronic meningitis. Cryptococcal antigen testing of the cerebrospinal fluid and the serum were both negative. The atypical morphology and the false-negative test may lead to delay of diagnosis and treatment.