Background: Metastases to the pituitary gland are rare events and usually indicate widespread malignant disease. Most common symptoms of pituitary metastases are diabetes insipidus and visual disturbances. The lung and breast are the most common sites of primary tumors that metastasize to the pituitary gland. Pituitary metastasis of gastrointestinal tractus is extremely rare.
Case presentation: A 53-year-old woman was given chemotherapy for colon cancer with liver metastases. During chemotherapy she complained from polyuria and polidypsia and she was referred to our endocrinology clinic. Water deprivation test was compatible with central diabetes insipidus. The hormones of anterior hypophysis were with in normal limits. Pituitary MRI showed a sellar mass lesion of 7.5×5.5×8.5 mm in dimesion which was accepted as a metastatic lesion.
Conclusion: The most common malignancies which cause pituitary metastasis are breast and lung cancer. This is an extremely rare case of central diabetes insipidus which is due to pituitary metastasis of colon cancer.