Diabetes Insipidus and Anterior Pituitary Insufficiency Due to Breast Cancer Metastasis

ABSTRACT

Metastases from breast cancer to the pituitary gland are uncommon. We present a 35-year-old woman with diabetes insipidus and anterior pituitary insufficiency resulting from breast cancer metastases to the pituitary gland. The patient presented with reduced consciousness, fatigue, polyuria, and polydipsia. Hypernatremia (sodium: 154 mmol/L), hypostenuria (urine density: 1001), and hypopituitarism were present on laboratory evaluation. Magnetic resonance imaging (MRI) revealed heterogeneous pituitary gland, thickened pituitary stalk (8mm), and loss of normal hyperintense signal of the posterior pituitary. Based on the clinical, laboratory, and MRI findings, the patient was diagnosed with diabetes insipidus and anterior pituitary insufficiency due to pituitary metastases from breast cancer. She received desmopressin, L-thyroxine, and prednisolone, which resulted in improvement of her symptoms and laboratory results. The patient, who also received Gamma Knife radiosurgery and chemotherapy, died six months later due to disseminated metastases. Although pituitary metastasis is rare, it should be kept in mind in patients with breast cancer since early detection and treatment can improve symptoms of patients.