Diagnosis, PET/CT imaging, and treatment of extranodal non-Hodgkin lymphoma in keratinized gingiva: a case report.

A 58-year-old patient who smoked and had uncontrolled type 2 diabetes mellitus was referred to our clinic. The patient had a suspicious asymptomatic lesion that was diagnosed as B-cell non-Hodgkin lymphoma (NHL). Immunohistochemistry revealed intense and diffuse expression of CD20, CD10, BCL-6, and Ki-67. A positron emission tomography/computed tomography (PET/CT) scan showed focal pathological uptake of F-18-fluorodeoxyglucose only in the subcutaneous tissue anterior to the left maxillary sinus. After lesion excision and five courses of chemotherapy, PET/CT scans demonstrated complete resolution of the lesion. Smoking, uncontrolled diabetes mellitus, and periodontal disease might be predisposing factors for oral NHL.