Princess presented to the Cornell University Hospital for Animals with a 2 month history of polyuria and polydispsia and right-sided nasal discharge. Antibiotic therapy prior to presentation was unsuccessful. Physical exam showed mucopurulent ocular (OD) and nasal discharge on the right side. Bloodwork showed mild hypercalcemia, hypernatremia, hyperchloremia, and hyperproteinemia. Ophthalmology consult diagnosed bilateral KCS and treatment with Optimmune was started. Cause for polyuria and polydipsia was diagnosed by ruling out all other causes for polyuria except diabetes insipidus and psychogenic polydipsia. Central diabetes insipidus was distinguished from nephrogenic causes and psychogenic polydipsia using the Desmopressin response test which confirmed central diabetes insipidus. Three months later Princess returned with progressive depression. Imaging studies found a polyostotic bone lesion involving the base of the skull. She was euthanized and histopathology found evidence of bone remodeling and medullary fibroplasia surrounding the pituitary, however the pituitary was lost during sampling.