A case of perithyroidal actinomycosis in a child with pyriform sinus fistula

Abstract

Although actinomycosis may occur anywhere in the body, the most common site of this infection is the head and neck region. Actinomyces, the usual cause of actinomycosis, is a commensal bacterium with low pathogenicity that is a normal resident in the oral cavity, thus odontogenic injury is a common antecedent event. Therefore, cervicofacial actinomycosis commonly occurs in the mandibular area, submandibular gland, and tongue in order of decreasing frequency. The authors encountered a case of a child with a history of slowly progressing swelling in the left side of the lower neck and no history of oral or odontogenic trauma. A pyriform sinus fistula found in this patient could be the unusual root of the cervicofacial actinomycosis occurring in the perithyroidal region, via a direct connection between the site of infection and the upper aerodigestive tract.