The number of opportunistic infections in the central nervous system (CNS)
has been steadily increasing because of a rising number of immunocompromise
d patients. A rare form of CNS infection can be caused by Chaetomium specie
s, one of the largest genera of saprophytic ascomycetes. The CNS lesions in
the present case were caused by Chaetomium atrobrunneum. The main characte
ristic of almost all Chaetomium species is presence of hairs or setae cover
ing the ascomata. Microbiological studies are the only definitive way to co
rrectly identify this fungal organism. The rapid evolvement of the cerebral
infection suggests that the brain tissue provides a favorable enviroment f
or growth and proliferation of these fungi. This is the second documented c
ase of a fatal brain abscess caused by Chaeotomium atrobrunneum, and the fi
rst case report in a bone marrow transplant patient. Copyright (C) 1999 by
W.B. Saunders Company.