Abstract #1404147: Adipsic Diabetes Insipidus in a Patient with Aggressive Suprasellar Mature Teratoma

Abstract

Diabetes insipidus (DI) can be life-threatening if not properly diagnosed and managed. There are many etiologies of central diabetes insipidus including neoplasm, vascular disease, trauma, autoimmune disease, infection, granulomatous disease, drugs, and genetic disease. This report presents a patient who developed adipsic DI secondary to a rare etiology, a suprasellar mature teratoma. A 37-year-old man with no significant past medical history presented to the hospital for worsening altered mental status (AMS) for 5 months, headaches, and polydipsia. Hypernatremia with a sodium level of 175 was noted. Magnetic resonance imaging (MRI) of the brain showed a large, heterogenous, mixed solid cystic suprasellar mass measuring 3.4 x 2.6 x 2.7 cm invading the suprasellar structures and extending to the third ventricle with mass effect on the hypothalamus, thalami, and optic chiasm. Panhypopituitarism with DI, hypothyroidism, adrenal insufficiency, and hypogonadism was diagnosed. Open craniotomy for surgical resection of the mass was performed. Pathology revealed endodermal tissues representing small and large intestine and stratified keratinizing and nonkeratinizing squamous epithelium in a background of hemorrhage, fibrosis, chronic inflammation, and mucin consistent with a suprasellar mature teratoma. He was discharged on desmopressin 1 mcg subcutaneously twice daily, hydrocortisone, and levothyroxine. He presented 7 months later for AMS and severe hypernatremia on desmopressin 6 mcg subcutaneously twice daily. There was regrowth of the suprasellar mass with interval worsening in size (3.5 x 3.7 x 3.1 cm) and increased mass effect on the left internal carotid artery, anterior communicating artery, and third ventricle. Subsequently, he underwent endoscopic cyst fenestration and ventriculoperitoneal shunt placement. Panhypopituitarism persisted, and he remained obtunded. He was hospitalized for 2 months, and repeat MRI of the brain showed an interval increase in the size of the mass (4.7 x 3.6 x 3.3 cm) with surrounding vasogenic edema and mass effect on the optic chiasm, hypothalamus, and third ventricle concerning for right ventricular entrapment. Due to the aggressive nature of the tumor, it was deemed inoperable and the patient underwent comfort care measures. Suprasellar mature teratomas are rare tumors which respond to surgical resection with a 10-year survival rate of 93%. Hypothalamic damage from these tumors can lead to an inability to maintain thirst response which can be dangerous in central DI as severe hypernatremia can develop. In these patients, it is vital to evaluate for other pituitary hormone deficiencies.