Primary diffuse large B-cell lymphoma of mandible masquerading as toothache

Abstract

Background Diffuse large B-cell lymphoma (DLBL) is an aggressive, fast-growing form of non-Hodgkin disease, with rare manifestation in the mandible as the primary site. The absence of pathognomonic features in this localization often leads to misdiagnosis as an odontogenic process or to delayed diagnosis. We report here a case where nonodontogenic jaw pain mimicked toothache, prompting multiple dental interventions before the persistence of pain and atypical findings led to the consideration of a malignant etiology. Case Summary A 54-year-old male presented to our oral medicine service for dental clearance before radiation for mandibular lymphoma. He had presented to his dentist for evaluation of right-sided jaw pain a few months earlier. On presentation, he had no lymphadenopathy or paresthesia, and his oral evaluation was within normal limits. Radiographic examination showed a deep restoration with pulpal proximity in tooth #31, widened periodontal ligament, loss of lamina dura, and diffuse periapical rarefaction. Tooth #31 was diagnosed with pulpitis, and the patient underwent root canal treatment. After a brief period of quiescence, the jaw pain returned, and the fractured cusp of tooth #30 was bonded to address the symptoms. Despite these measures, the jaw pain persisted, and tooth #31 gradually developed extreme compressive mobility. Imaging revealed extensive alveolar bone loss, furcation involvement, and floating molars. While extracting #31, a large osseous defect was visualized. This raised suspicion of a nonodontogenic etiology for the patient's pain and prompted referral for bone biopsy. Microscopic examination of the jaw specimen showed a tumor composed of neoplastic lymphocytes with large nuclei, prominent nucleoli, and scattered mitotic figures. Immunohistochemical staining was positive for CD45, CD20, CD79 a, and BCL-6. Positron emission tomography/computed tomography showed a solitary lytic lesion measuring 3.5 cm in length, with intense metabolic activity in the right mandibular body. Oncologic workup confirmed primary extranodal DLBL, and the patient was started on chemotherapy. Follow-up imaging showed marked reduction in metabolic activity (3.8 compared with previous 44.4). The patient subsequently received low-dose radiotherapy for residual disease in the mandible and achieved remission. Conclusions Dental providers should consider malignancy, including lymphoma, although uncommon, in the differential diagnosis of jaw pain, particularly when thorough evaluation fails to disclose a dental etiology, routine dental interventions fail to control symptoms, or there are atypical clinical or radiographic findings.