Sellar Masses that Present with Severe Hyponatremia.

Area of Science:

• Neuroendocrinology
• Neurosurgery
• Oncology

Background:

• Sellar lesions are an underrecognized cause of hyponatremia.
• This study investigates the incidence and characteristics of hyponatremia in patients with sellar masses.

Purpose of the Study:

• To determine the frequency of hyponatremia as an initial presentation of sellar lesions.
• To analyze the types of sellar pathologies associated with hyponatremia.
• To evaluate the outcomes of surgical intervention for these conditions.

Main Methods:

• Retrospective review of 282 patients undergoing endonasal surgery for de novo sellar masses over 5 years.
• Documentation of pathology, serum sodium levels, pituitary hormonal status, and treatment course.
• Analysis of hyponatremia incidence across different sellar pathologies.

Main Results:

• 16 patients (5.7%) presented with severe hyponatremia (mean serum sodium 115 ± 6 mmol/L).
• Sellar arachnoid cysts (37.5%) and Rathke's cleft cysts (14.3%) were most frequently associated with hyponatremia.
• Pituitary apoplexy or cyst rupture occurred in 50% of hyponatremic patients, with universal anterior pituitary dysfunction (81% hypoadrenalism, 69% hypothyroidism).

Conclusions:

• Severe hyponatremia is a significant presenting sign in 5.7% of sellar pathology cases, particularly arachnoid cysts, RCCs, and pituitary apoplexy.
• New-onset severe hyponatremia warrants pituitary hormonal evaluation and brain imaging.
• Surgical resection and hormonal correction effectively resolve recurrent hyponatremic episodes.