Primary non-Hodgkin's lymphoma of the frontal sinus: how we diagnosed it.

Isolated primary non-Hodgkin's lymphoma of the frontal sinus is rare. We describe the case of a middle-aged man who came to us with signs of orbital cellulitis complicating an acute infected frontal mucocele. His condition was initially controlled with medical therapy and subsequent endoscopic sinus surgery, but his symptoms eventually returned. We were able to diagnose the lymphoma only by approaching the sinus externally to obtain a biopsy. This case highlights the importance of making a full visual inspection of the involved sinus in order to avoid missing an unexpected, albeit a rarely encountered, pathology.