Diabetes insipidus due to pituitary metastasis of breast cancer
Ayse Kubat Uzum, Ilkay Kartal, Meral Mert & Ferihan Aral
Introduction: We have reported a case of breast carcinoma complicated by diabetes insipidus due to pituitary metastasis.
Case: A 47 years old woman had been referred our clinic with the symptoms of polyuria, polydypsia, weight loss, and fatigue. She had a diagnosis of breast carcinoma for six years, underwent radically mastectomy, chemotherapy and radiotherapy, subsequently. Vertebral metastasis was detected and local radiotherapy was performed six months before admission. Symptoms of polyuria, polydypsia began in the first years of the disease and got worse over time. Her skin turgor was reduced and her mouth was completely dry. She had 11L urinary output and oral intake in a day. Laboratory findings on admission were as follows: serum sodium: 144 mmol/L (135146 mmol/L), potassium: 4,9 mmol/L (3.55.1 mg/dl) and chloride: 100 mmol/L (95107 mmol/L), serum creatinine: 0.4 mg/dL (0.71.4 mg/dl). Free T4: 17.7 pmol/L, TSH: 1.23 mIU/L, LH: 3,2, FSH: 1,9, estradiol: 23 mIU/L, Prolactin: 0,6 ng/ml, cortisol: 21.3 microg/dl. According to urinalysis, the density of the urine was 1000. Urinary and plasma osmolality were 101 and 324 mOsm/L, respectively. Her gonadotropine levels were not compatible with menoposis. On the day after admission, dDAVP 0,1 mg/day was administered orally. The urinary output decreased to 3 L/day and the oral intake was 4 L/day. Magnetic resonance imaging of sella revealed a huge mass filling sella turcica, arising from suprasellar cistern, surrounding cavernous sinus and compressing to optic chiasm and infindubulum. The mass was compatible with breast cancer metastasis to hypophysis, and radiotherapy was performed. Three months after irradiation, panhypopituitarism had developed. She is still alive under full replacement therapy.
Conclusion: Extension of breast cancer to the pituitary gland is a rare and late complication. Although life expectancy is limited in advanced breast cancer, hormonal insufficiency should be corrected to increase the life quality.