Lymphocytic hypophysitis is a rare but important cause of pituitary hypofunction which predominantly affects young women in the peripartum period. It is believed to be an autoimmune disorder with an association with other autoimmune disorders and expression of anti-pituitary cytosolic and anti-nuclear antibodies. Clinically, it presents most frequently with symptoms and signs attributable to pituitary hypofunction, headache, visual disturbance and amenorrhoea. It is difficult to distinguish lymphocytic hypophysitis from a pituitary adenoma on pre-operative imaging and definitive diagnosis rests on histology which classically demonstrates destruction of anterior pituitary acini by an inflammatory infiltrate rich in plasma cells and T lymphocytes. Surgical management therefore plays a crucial role to obtain a histological diagnosis and to relieve pressure effects on the optic apparatus in patients with visual disturbances.