Blastomycosis: The Great Pretender.

Blastomycosis is an endemic fungal infection caused by Blastomyces, a soil-dwelling dimorphic fungus found predominantly in North America. In this pictorial essay, we illustrate the varied imaging features of blastomycosis along with a brief description of the epidemiology, clinical aspects, and differential diagnosis, emphasizing clues that can help radiologists arrive at this diagnosis.