A case of actinomycosis occurred in the upper lip

Actinomycosis is a chronic suppurative disease caused by the Gram-positive anaerobic bacterium actinomycetes, an endemic oral bacterium. This infection is not unusual in the head and neck region causing well known symptoms such as plate-like induration, trismus, and multiple abscess formation. However, lip Actinomycosis rarely occurs and it is important to differentiate it from soft tissue diseases including minor salivary gland tumors and cysts. In this case report, we present our experience to diagnose and treat upper lip actinomycosis. The case was a 64-year-old Asian woman who had extraoral erythema with slight swelling in her left upper white lip. There was a palpable, well-defined, approximately 10 mm submucosal hard mass. The STIR image in MRI exam clearly showed the lesion with high signal which was clinically suspected to be a minor salivary gland tumor. Instead of an acquisition of tumor characters, the biopsy did lead to incision and pus discharge of the lesion. Histopathological examination for the specimen was carried out using HE, PAS and Grocott staining which provided evidence of characteristic features for Actinomycosis. The surgical intervention and the postoperative course with oral amoxicillin for 4 weeks completely cured the lesion. Lip mass lesions should be carefully differentiated considering possible infectious diseases like Actinomycosis.