Phialophora verrucosa and Other Chromoblastomycotic Fungi

Abstract

The tissue form of the agents of chromoblastomycosis is quite unique among human pathogenic fungi. The yeast cells, hyphae, pseudohyphae, or spherules that are typical of other human pathogenic fungi are not customarily observed. Instead, richly pigmented brown cells (Figure 1) that form transverse septations are seen by microscopic observation of the lesions of chromoblastomycosis. In some instances, multicellular bodies that form both longitudinal and transverse septa as they divide (muriform cells) are observed. Early investigators of chromoblastomycosis (Medlar, 1915), thinking that these muriform cells represented the development of a sclerotium, named these cells “sclerotic cells” or “sclerotic bodies.” The cells have also been called “Medlar bodies,” “chromobodies,” “fumagoid bodies,” and even “copper pennies” by various observers (McGinnis, 1983). For convenience, they will be referred to herein as sclerotic cells, even though it is recognized that the term may be somewhat misleading, since the multicellular form seen in tissue is not a sclerotium, nor does it represent a stage in the development of a sclerotium.