Background: A 29-year-old man was referred to a multidisciplinary pituitary clinic with a 3.5-year history of central diabetes insipidus, initially presumed to be idiopathic based on a normal MRI scan of the pituitary gland. Subsequent scanning revealed a suprasellar mass, which demonstrated progressive enlargement on serial imaging. He also developed hypogonadotropic hypogonadism.
Investigations: Measurement of levels of serum morning fasting cortisol, adrenocorticotropic hormone, total testosterone, luteinizing hormone, follicle-stimulating hormone, prolactin, insulin-like growth factor 1, TSH and free T(4), MRI of the pituitary gland and a transsphenoidal biopsy of a pituitary mass were performed.
Diagnosis: Lymphocytic hypophysitis presenting with diabetes insipidus, with development of hypogonadotropic hypogonadism and a suprasellar mass.
Management: The patient was treated with intranasal desmopressin and transdermal testosterone. The underlying lymphocytic hypophysitis was initially managed conservatively with serial MRI and visual field testing. No immunosuppressant medication was given and, aside from the diagnostic transsphenoidal biopsy, no surgical intervention was required. He subsequently developed secondary hypothyroidism, secondary adrenal insufficiency and growth hormone deficiency. These disorders were managed with levothyroxine and prednisone.