Actinomycotic ulcer of the oral mucosa: an unusual presentation of oral actinomycosis

Although the oral mucosa is often the site of entry of actinomyces into the deeper tissues, actinomycosis in the oral mucosa is extremely rare. Actino mycotic lesions are usually described as either single or multiple abscesse s or indurated masses with hard fibrous walls and soft central loculations. Actinomyces israelii is the principal cause of human actinomycosis. We pre sent a rare case of actinomycosis caused by Actinomyces odontolyticus; it p resented primarily as a long-standing ulcer of the oral mucosa mimicking a squamous cell carcinoma.