Chromoblastomycosis

Abstract

Abstract Chromoblastomycosis is a chronic fungal infection of the skin and subcutaneous tissues characterized by the presence of nodular, verrucous lesions often of the lower extremities. Upon histopathologic examination of infected tissues, the characteristic finding is single or multiple sclerotic bodies, which are dark brown septate fungal cells that resemble yeast forms (See Color Fig. 26–1 in separate color insert). Sclerotic bodies often are referred to as muriform cells, with the term muriform designating the presence of vertical and horizontal septa of the cells. While chromoblastomycosis is caused by several species of dematiaceous, or pigmented, fungi, the most common causative organism is Fonsecaea pedrosoi. The disease is usually chronic, localized, and is rarely life-threatening. Surgical resection and cryotherapy are effective for small lesions, while antifungal agents, including itraconazole and flucytosine, are sometimes effective in more extensive disease. For the purposes of this chapter, chromoblastomycosis is defined as a chronic infection of the skin or subcutaneous tissues caused by dematiaceous fungi and characterized by the presence of sclerotic bodies on histopathologic examination. Chromoblastomycosis is often referred to as chromomycosis, although these terms are not synonymous. The term chromomycosis has come to represent not only the classic definition of chromoblastomycosis, but also additional nonskin and subcutaneous infections due to dematiaceous fungi (Fader and McGinnis, 1988; Kwon-Chung and Bennett, 1992). Phaeohyphomycoses represent the broad group of fungal infections caused by dematiaceous fungi and are defined by the presence of yeast-like cells, hyphal forms, or pseudohyphae-like elements in tissue, but without the presence of sclerotic bodies as seen in chromoblastomycosis (Fader and McGinnis, 1988). Phaeohyphomycoses are distinct from chromoblastomycosis and are addressed in a separate chapter (See Chapter 17.).