Endocrine Abstracts

We report the MRI findings of an unusual case of posterior pituitary ectopia (PPE) in a young female patient with idiopathic diabetes inspidus (DI). She was 29 years- old and presented with polydipsia (7–8 lt/day), and polyuria (7–8 lt/day) that had been present for about 5 months. She had regular menstrual cycles. She didn’t have any history of significant medical illness or any history of head trauma. An 8-hour fluid deprivation test followed by desmopressin (DDAVP, 0.03 μg/kg SC) was performed in which the results were consistent with pituitary DI. She had complete correction of her thirst after DDAVP treatment was started (10 μg, bid,) and her water intake was limited to 3 L/d and urinary output decreased to 2.6 L/d. We evaluated the patient with dynamic pituitary MRI to see whether she had any problems in the hypothalamo-pituitary axis. Her pituitary MRI showed a normal appearing adenohypophysis without any space occupying lesions, the infundibulum was in the midline and of normal thickness. The pituitary bright spot was not observed at its normal location within the sella, instead we observed two discrete foci of hyperintensity at the median eminence of hypotalamus. Insulin hypoglycemia test revealed increased cortisol (>20 μg/dl) and growth hormone (>20 ng/ml) responses. Chest radiographs were normal. Analyses of lymphocyte subgroups for Sarcoidosis were in normal range. C-ANCA was negative for Wegener’s granulomatosis. Control MRI 6 months later revealed exactly the same findings as the initial MRI. This case is one of the few cases in the literature since it is a case of PPE with preserved anterior pituitary functions and without any space occupying lesion in the sella and traumatic or infiltrative lesion of the infundibulum.