Granulomatous lymphadenitis and splenitis associated with Monocillium indicum infection in a dog

This report describes severe generalized granulomatous lymphadenitis and splenitis in a 5-year-old, spayed female, Rottweiler dog with anorexia and diarrhea. There was replacement or effacement of much of the parenchyma of the lymph nodes and spleen by sheets of macrophages, multinucleated giant cells, and myriad nonpigmented fungal organisms, most of which appeared to be intracellular. These organisms were very pleomorphic, including large chlamydospore-like cells, small round yeast-like cells, and septate hyphae. A fungus identified as Monocillium indicum was isolated from lymph node tissue. To the authors' knowledge, this is the first report of infection with Monocillium in either humans or other animals.