Lymphocytic hypophysitis is a rare inflammatory disease of the pituitary gland that is being increasingly recognized as a cause of hypopituitarism. This condition may be due to an autoimmune pituitary destruction which usually occurs in young women during pregnancy or in the immediate postpartum period. We describe a case of cystic pituitary mass in a thirty-eight year-old woman presenting with nausea, vomiting, cold intolerance, blurring of vision and the presence of disagreeable odors for a one-month period. She had secondary amenorrhea and galactorrhea for three months. Combined anterior pituitary stimulation test confirmed the diagnosis of hypopituitarism. Magnetic resonance imaging scan with enhancement showed a huge cystic sellar mass with suprasellar extension and thickening of the pituitary stalk. Transsphenoidal exploration was performed with preoperative diagnosis of pituitary macroadenoma with cystic necrosis. Histological examination revealed lymphocytic hypophysitis characteristic of diffuse, dense lymphocytes and plasma cells infiltration with surrounding interstitial reactive fibrosis. Postoperatively, the patient's olfactory function returned to normal but combined anterior pituitary stimulation test showed persistence of hypopituitarism with mild hyperprolactinemia. Prednisolone, thyroxine and estrogen replacements were started and clinical symptoms were much improved. In summary, we report an extremely rare case of a woman with cystic lymphocytic hypophysitis with cacosmia and hypopituitarism, confirmed by histological examination.