Systemic phaeohyphomycosis (10)

The processes included in this group are infections that do not have the histologic features of either chromoblastomycosis or mycetoma and that have involve deep tissues. Cerebral phaeohyphomycosis is the most frequently reported systemic infection caused by black fungi. Other infections included in this category include infective endocarditis, pulmonary disease, septic arthritis, osteomyelitis, esophagitis, dialysis-associated peritonitis, and disseminated disease. Affected individuals are frequently immunocompromised, but both disseminated and localized deep infections have been seen in seemingly immunocompetent individuals. Most cases of cerebral phaeohyphomycosis present with symptoms and physical findings compatible with an intracerebral mass lesion. Headache is a frequent complaint, and development of hemiparesis may be due either to cortical brain abscess or brain stem invasion. CT scans show single or multiple variably enhancing masses with surrounding edema, which may not be distinguished from the findings seen with metastasis or high grade glioma. Frontal lobe white matter is the most common location for abscesses, but several other sites have been reported. Because of the nonspecific clinical features, cerebral phaeohyphomycosis is diagnosed when tissue samples are obtained either at the time of surgery for removal of a mass lesion or postmortem. Pigmented hyphae ate most often seen on histologic examination of involved tissues, and the identity of the causative organism is determined by culture. The single most common causative organism is Cladophialophora bantiana, which implicated in more than one third of reported cases. Other dematiaceous fungi that have been implicated include Wangiella dermatitidis, Ramichloridium mackenzii, Fonsecaea pedrosoi, Curvularia pallescens, Ochroconis gallopavum, and Bipolaris spicifera.