Localized oral blastomycosis mimicking actinomycosis

A case of blastomycosis limited to the oral cavity is presented. The disease apparently originated in the mandible and eroded into the oral cavity. Secondary bacterial infection of the sinus tracts resulted in a clinical picture that mimicked cervicofacial actinomycosis. Appropriate microbiologic studies, including culture confirmation of the causative organism, were necessary to establish a definitive diagnosis.