The dental surgeon can play an important role in the early referral of malignancy of the maxillary sinus, and should be familiar with the signs and symptoms of disease of the paranasal sinuses. Here we report a case of a 71-year-old male patient diagnosed with high-grade B-cell lymphoma of the maxillary sinus that was initially thought to be an odontogenic infection. We discuss the signs and symptoms of lymphomas and malignancy of the maxillary sinus.