Science and Education Publishing American Journal of Medical Case Reports 2374-216X 4 12 2016 12 23 Seller Mass in a Young Man with Diabetes Insipidus and Panhypopituitarism'What is the Diagnosis? 376 377 EN Smita Subramaniam Department of Internal Medicine, JPS Hospital [John Peter Smith], Fort Worth, Texas USA Bassam Ghabach Andrey Manov AJMCR20164122 10.12691/ajmcr-4-12-2 2016 9 1 2016 11 13 2016 12 21 Pituitary and suprasellar lesions can cause diabetes insipidus due to interruption of pathways carrying vasopressin and oxytocin to pituitary. Central diabetes insipidus is characterized by polyuria and polydipsia and is a direct result of deficiency of vasopressin. Midline mass lesions in brain and body warrant further workup for possible diagnosis of germ cell tumors. We present an interesting case of a young man with suprasellar brain lesion and diabetes insipidus with pan hypopituitarism where further workup revealed germinoma. Patient had a favorable outcome with surgery followed by radiation therapy.