Disseminated cutaneous infection with Mycobacterium kansasii: genotyping versus phenotyping.

Mycobacterium kansasii is a common and virulent pathogen. However, primary cutaneous M kansasii infection has rarely been reported, totaling to only 34 cases since 1965. This low incidence has not been explained, but probably is due to difficulty in culture or phenotyping. We describe the first reported case of cutaneous M kansasii diagnosed by genotyping, which is based on the DNA extracted from the formalin-fixed and paraffin-embedded tissue.