A patient with relapsed refractory acute myeloid leukaemia developed t
ypical fungal lung lesions despite intravenous amphotericin B prophyla
xis. Chaetomium globosum was cultured from the resected right lower lo
be. Histology showed branching hyphae negative for common Aspergillus
species by immunohistochemical staining. Previous reports of invasive
disease caused by Chaetomium and some applications of immunohistochemi
cal staining for Aspergillus are discussed.