A skin infection mimicking chromoblastomycosis by a Capnodialean fungus

Abstract

Most black fungi that are repeatedly involved in human infection belong to the order Chaetothyriales. Capnodialean melanized fungi often thrive in extreme environments like rock surfaces and hypersaline microhabitats. They are able to grow meristematically with very thick cellular walls, resembling muriform cells of agents of chromoblastomycosis. In this report we describe a member of the order Capnodiales causing a chromoblastomycosis-like infection in human skin. However, in tissue the fungus presented with toruloid hyphae and intercalary, chlamydospore-like conidia with transversal septa, rather than with muriform cells. Judging from ITS rRNA sequences, the fungus is related to, but clearly different from, the genera Catenulostroma and Pseudotaeniolina; members of these genera are environmental and only rarely occur on human hosts.