A Case of Cutaneous Cryptococcosis―Successful Diagnosis by PCR and Sequencing Analysis―

Abstract

An 87-year-old woman had erythema with slight itcing in her left forearm. Although cryptococcosis was suspected histopathologically, laboratory culture test for fungi was negative. For PCR analysis, DNA was extracted from both frozen sections and formalin-fixed, paraffin-embedded specimens of this case. DNA was also extracted from Cryptococcus neoformans (C. neoformans) strains ; two reference strains and two clinical strains isolated from cases of cryptococcal meningitis with AIDS. From all these DNA samples, a 416-bp fragment was amplified by PCR using primers specific for C. neoformans. Sequencing analysis confirmed that a specific region of C. neoformans genome was amplified. The PCR and sequence analysis revealed C. neoformans DNA from two additional culture-negative cases, a case of pulmonary cryptcoccosis associated with AIDS (paraffin-embedded lung specimens) and a case of meningitis (spinal tap liquor sample). PCR and sequencing analysis might be useful for diagnosis of cryptococcal infections when culture data are not available.