Inflammatory pseudotumor of the paranasal sinuses is a rare, chronic, benign entity that results in symptoms according to the location of the lesion. Sometimes it can be locally invasive, so it must be distinguished from malignant processes. We report a case of a patient who presented with headache and seizures in whom an inflammatory pseudotumor was diagnosed histologically. To our knowledge there are not documented cases of frontal sinus involvement and associated seizures due to intracranial invasion. The differential diagnosis with other entities is difficult despite imaging studies so the biopsy and pathology are key determinants.