Rare Localization of Actinomyces israelii: Clinical, Radiological, and Histopathological Insights from a Lingual Case

Actinomycosis is a rare, chronic infection caused by Actinomyces israelii, a Gram-positive anaerobic bacterium that commonly inhabits the human oral cavity. Lingual involvement is extremely uncommon, accounting for less than 3% of reported cases, and poses a diagnostic challenge due to its ability to mimic both benign and malignant lesions. The present paper reports the case of a 38-year-old male presenting with a six-month history of swelling in the posterior region of the tongue, which exhibited cyclical size variation and fistula formation. Clinical and radiological evaluation revealed a solid mass extending into the mylohyoid and genioglossus muscles. Surgical excision was performed, followed by histopathological analysis, which confirmed the diagnosis of lingual actinomycosis. Postoperative antibiotic therapy was administered, and the patient showed complete recovery without recurrence. Lingual actinomycosis is a rare but important differential diagnosis for submucosal tongue lesions. A multidisciplinary approach involving imaging, surgical intervention, histological examination, and appropriate antibiotic therapy is essential for accurate diagnosis and effective treatment. Surgical excision combined with antibiotic therapy provides optimal outcomes, with long-term follow-up recommended to monitor for recurrence.