About the ten patients that had olfaction alteration, the access route were: transsphenoidal in eight patients (four multi-producer adenomas, one GH, one ACTH, and one non-producer, as well as one craniopharyngioma), and the transcribriform approach was used in two cases (one brain abscess and one olfactory groove meningioma). The gene discussed is POMC; the disease is craniopharyngioma.