Background: Actinomycotic osteomyelitis is an infection in soft tissues and/or bones, being associated with trauma or a previous nonspecific infection. This article presents an unusual case of mandibular osteomyelitis caused by Actinomyces.
Case report: A 19-year-old male patient was referred for endodontic treatment of the lower right first molar about 16 months ago and removal of lower right third molar approximately 3 years before. The panoramic radiography showed change in bone density in the region of ill-defined mandibular angle boundaries, and the computed tomography (CT) showed mixed density image in the mandibular angle, with discreet expansion of cortical vestibular and lingual. Biopsy was performed, and content was aspirated in small quantity and purulent tissue fragments were sent to anatomical-pathological examination. The collected purulent secretion was colored for cytopathologic study, which showed infection by Actinomyces.
Discussion: In this case, the causative agent was Actinomyces, which makes it even more unusual. The origin of the microorganism has not been clearly established; however, the diagnosis allowed long-term treatment with antibiotics, which has resulted in the resolution of the case.