EMP is a rare plasma cell neoplasm accounting for 1-3% of all plasma cell malignancies. Approximately 80% arise within the head and neck, most commonly in the upper aerodigestive tract. Involvement of the base of the tongue with associated cervical lymphadenopathy is uncommon and may mimic squamous cell carcinoma (SCC) or lymphoma, posing a diagnostic challenge. Case Presentation: A 59-year-old man presented with a progressively enlarging left-sided neck mass of five months duration. Flexible nasendoscopy revealed a smooth lesion at the left base of the tongue. CT demonstrated a tongue base mass with cervical lymphadenopathy. Histopathological examination of biopsy specimens showed mature plasma cell proliferation positive for CD79a, CD138, and CD38 with lambda light-chain restriction and a low Ki-67 proliferative index, while markers for SCC and lymphoma were negative. PET-CT demonstrated intense uptake confined to the tongue base and regional cervical/supraclavicular lymph nodes. Bone marrow biopsy and flow cytometry excluded systemic multiple myeloma (MM), confirming a diagnosis of localized extramedullary plasmacytoma with regional nodal involvement. Management and Outcome: Following multidisciplinary team discussion, the patient received radical radiotherapy (50Gy in 25 fractions over five weeks), achieving an excellent initial clinical response. Ongoing surveillance includes endoscopic assessment, serial paraprotein monitoring, and long-term follow-up for potential progression to multiple myeloma. Conclusion: This case highlights the importance of considering EMP in the differential diagnosis of tongue base lesions presenting with cervical lymphadenopathy. Comprehensive evaluation usng histopathology, immunohistochemistry, PET-CT, and bone marrow examination is essential to distinguish localized EMP from systemic plasma cell disorders. Early multidisciplinary management with definitive radiotherapy offers excellent local disease control preserving function. This rare presentation adds to the limited literature on tongue base EMP with regional nodal involvement and underscores the need for continued long-term surveillance.

TBA