Regular resident becomes aggressive enemy: Diagnosed on cytology

Actinomycosis, an oral cavity commensal, causes cervicofacial infection in patients associated with an immunosuppression state and local mucosal injuries. Bone involvement by this commensal is rare. In the present case, we report a case of left peri mandibular soft tissue, soft to firm, tender swelling in a 39-year-old immunocompetent male diagnosed as Actinomycosis infection on fine needle aspiration cytology (FNAC) and cell block preparation. A microorganism which is an oral cavity commensal, not commonly infective in immunocompetent, rarely shows bone involvement, show splendore hoeppli phenomenon, GMS and PAS stains help for diagnosis. Is it bacteria or fungi?imageActinomycosis in immunocompetent individuals is rare. Bone involvement in cervicofacial actinomycosis is uncommon. Cytopathology examination may help in early diagnosis and efficient management.