Lingual Actinomycosis Clinically Simulating Nodular Median Rhomboid Glossitis: Literature Review and Report of Additional Case

Actinomycosis is an uncommon, subacute to chronic, suppurative bacterial infection caused by Actinomyces Israelii. About 3% of all actinomycosis cases occur in the tongue, often affecting adult patients (mean age, 50 years). The clinical characteristics of actinomycosis can resemble malignant or benign tumors, and other infectious diseases. A 56-year-old woman was referred presenting an ulcerated lesion on the tongue 1 year ago. Intraoral examination revealed an edematous nodular lesion with an ulcerated surface, slightly symptomatic, on the midline dorsum of posterior tongue, suggesting nodular median rhomboid glossitis. Cytology smear was negative for fungus. After excisional biopsy, histopathological examination showed a chronic inflammatory infiltrate supported by a fibrovascular connective tissue stroma, and at the deepest part, broad basophilic areas surrounded by neutrophils, containing numerous filamentous bacilli, which were highlighted by Gram and Groccott-Gomori staining. The final diagnosis was lingual actinomycosis. Oral amoxicillin treatment (8/8 h for 2 weeks) was started, and after 1-month complete resolution was observed. Lingual actinomycosis is a rare lesion that must be recognized by dentists, because its early diagnosis and correct treatment reduce the possibility of a clinical complication that compromises the patient’s quality of life. Noteworthy, when located on the midline dorsum of posterior tongue, actinomycosis can simulate nodular median rhomboid glossitis, expanding its spectrum of clinical differential diagnosis.