Primary pituitary lymphoma in immunocompetent patients is an exceedingly rare clinical entity. We report the case of a 41-year-old woman with initial polydipsia and polyuria. When laboratory evaluation revealed panhypopituitarism, a pituitary enhanced MRI was performed and was suggestive of a pituitary adenoma. Obstructive hydrocephalus provoked by enlarged sellar mass was also demonstrated during observation, and a shunt procedure following lesion resection was carried out. Histopathological examination and immunophenotyping verified diffuse large B-cell non-Hodgkin's lymphoma. No systemic disease was found on staging of the patient. We will also review the clinical, radiological features and outcomes of 28 cases that have been reported since 1993.