Primary frontal sinus lymphoma is a very uncommon disease. In all the previously reported cases, the presenting symptoms have been due to the tumor mass effect. We present an unusual case report of an immunocompetent patient who presented with facial palsy, and then progressively developed other cranial nerve palsies over several months. He was later diagnosed with diffuse large B cell lymphoma originating from the frontal sinus. The patient underwent chemotherapy, but eventually had to receive autologous peripheral blood stem cell transplantation. He is currently disease-free. The clinical course, diagnostic workup, and therapeutic outcome are described.