This report describes the clinical and pathological characteristics of two patients with lymphocytic hypophysitis (LHy) and two with infundibuloneurohypophysitis (INHy). Two of the patients were women and two were men, and their ages were between 27 and 38 years old. This disease was not associated with either pregnancy or the postpartum period in the female patients. Two of the patients presented with diabetes insipidus, one with panhypopituitarism and right abducens paralysis and one with headache and galactorrhea. At presentation three of the patients had mild to moderate hyperprolactinemia and one had low prolactin levels. All four had abnormal magnetic resonance imaging (MRI): focal nodular enlarging of the infundibulum and normal hypophysis in one, expanding sellar masses in two, and diffusely thickened stalk with slightly enlarged pituitary gland in one. Three cases showed no sign of adenohypophysial deficiency with stimulation tests. One patient had associated chronic lymphocytic thyroiditis. Of the first three patients, one patient underwent transcranial and two underwent transnasal transsphenoidal (TNTS) surgery for mass excisions since they were thought to have pituitary tumors. Endoscopic endonasal transsphenoidal biopsy was performed in the last one with a suspicion of LHy. The pathological and immunohistochemical examinations revealed lymphocytic infiltration. Hyperprolactinemia resolved with surgery in two patients and one developed diabetes insipidus as a complication. We conclude that LHy and infundibuloneurohypophysitis should be considered in the differential diagnosis of the mass lesions of the sellar region and also should be kept in the mind for the etiopathogenesis of cases of hyperprolactinemia, galactorrhea and diabetes insipidus. In suspected cases endoscopic endonasal biopsy for the histopathological diagnosis can be a safe approach.