Introduction: Langerhan cell histiocytosis (LCH) is a rare cause of eosinophilic granulomatous inflammation that can affect multiple organ systems, mainly diagnosed in children. Hypothalamic-pituitary axis involvement is well established and is the characteristic intracranial manifestation of LCH. Patients can present with several presentations including anterior pituitary axis failure; however, the most common presentation is Diabetes Insipidus (DI). Here, we present a rare case of isolated pituitary LHC in male adult. Clinical Case: 47 years old gentleman presented with 4 week history of insidious headaches associated with persistent nausea. He also noticed drooping of his left eyelid and presented to hospital with complete ptosis. His CT head did not show any abnormalities. However finding on his MRI brain were consistent with a central skull base inflammatory process centred on the pituitary, extending cranially to the chiasm and third ventricular floor as well as laterally to the cavernous sinuses. His anterior pituitary profile was as follow: LH - 0.7 U/L (1.2-8.6 U/L), FSH - 4.2 U/L (1.3-19.3 U/L), Testosterone