Background: Non-Hodgkin's lymphomas (NHL) are a group of neoplastic disorders originated from the lymphoreticular cells. The occurrence of primary lymphoma in the oral cavity is uncommon and comprises only 2% of all extra-nodal lymphomas. The aim of this study was to introduce a case of NHL in the oral cavity, present its signs and differentiate it from other similar lesions.

Case Report: A 49 year-old woman referred to a dentist with a history of second right maxillary premolar pain and alveolar swelling in the region underwent the tooth extraction with a diagnosis of odontogenic infection. One week after the tooth extraction the patient referred to dentist with a complaint of swelling on her tooth. An incisional diagnosis of a primary large B-cell lymphoma was made based on the histopathological and immunohistochemical examinations and the patient referred to medical oncologist for treatment.

Conclusion: Classically, no clinical features of the lymphoma were seen in the jaw bones. Swelling, ulcer or discomfort may be present in the involved region, or it may mimic a periapical disease or a benign condition. These types of lymphomas can clinically present with symptoms of inflammatory endo-periodontal lesion as pain and local discomfort. Any delay in diagnosis will worsen the prognosis so it is important to detect the signs and symptoms of NHL.