Diffuse Large B-cell Lymphoma at the Base of the Tongue: A Rare Diagnostic Entity in Imaging

Primary lymphoma of the tongue base is exceptionally rare and often presents with nonspecific clinical features, making early diagnosis challenging. We report the case of a 47-year-old male, a chronic smoker with poor oral hygiene and no notable medical history, who presented with a painless mass at the base of the tongue and mild lingual discomfort. Initial empirical antibiotic therapy for a presumed abscess was ineffective. Magnetic resonance imaging revealed an infiltrative lesion with ipsilateral submandibular lymphadenopathy. Histopathology confirmed diffuse large B-cell lymphoma (DLBCL). Fluorodeoxyglucose (FDG)-PET/CT staging demonstrated localized disease (Ann Arbor stage IEA). The patient was treated with six cycles of rituximab, cyclophosphamide, doxorubicin (hydroxydaunorubicin), vincristine (Oncovin), and prednisone (R-CHOP) immunochemotherapy and intrathecal methotrexate prophylaxis. Post-treatment imaging confirmed complete remission. Primary involvement of the tongue base by DLBCL is an uncommon presentation that can mimic benign or infectious processes. Imaging and histopathology play key roles in diagnosis, while systemic immunochemotherapy remains the mainstay of treatment. Early consideration of lymphoma in tongue base masses unresponsive to medical therapy enables timely diagnosis and effective management.