Central Diabetes Insipidus in A Young Man with Intracranial Germ Cell Tumors: A case report

Abstract Background Central diabetes insipidus (CDI) in patients with intracranial germ cell tumors (GCTs) could develop due to suprasellar involvement or postoperative complication after transsphenoidal surgery (TSS). However, it is important to early recognize the pre-existing CDI caused by GCTS with normal sodium (Na + ) level before surgery. Case presentation A 25-year-old male presented with progressive fatigue, weakness, polydipsia and loss of libido in the past one year. Laboratory finding was unremarkable without hypernatremia. Hormonal testing indicating anterior pituitary insufficiency. Brain m agnetic resonance imaging showed two mass lesions in the sellar/suprasellar and pineal regions with obstructive hydrocephalus. The patient developed polyuria with hypernatremia after 6-hour fasting and TSS with incisional biopsy. Diagnosis of intracranial GCTs with CDI was confirmed by pathology and desmopressin test. Without surgical damage to posterior pituitary or tumor resection which might led to postoperative CDI, pre-existing CDI before surgery could be unrecognized by normal serum Na + and unrestricted water intake. Conclusions Clinicians should notice the typical manifestations of intracranial GCTs, especially in CDI, to avoid potential complications. Fluid restriction before surgery is a risk factor to develop hypernatremia caused by CDI that was masked by polydipsia before surgery.