Giant sellar aneurysm presenting with arginine vasopressin deficiency: a rare case report.

Giant aneurysms are rare vascular anomalies that can induce symptoms through compression of neural structures. This report describes a case of a giant sellar aneurysm initially manifesting as diabetes insipidus (DI), challenging conventional diagnostic paradigms for sellar mass lesions. Although DI typically arises from antidiuretic hormone (ADH) deficiency, its presentation as the primary symptom of a giant sellar aneurysm is exceedingly uncommon. The distinctiveness of this case lies in the occurrence of DI, likely due to aneurysmal compression of the pituitary gland, underscoring the imperative to include aneurysms in the differential diagnosis of sellar lesions. Giant sellar aneurysms are frequently misdiagnosed as pituitary adenomas, particularly when atypical symptoms are present. Through multidisciplinary collaboration, this case was successfully managed, yielding valuable clinical insights. This report not only advances the understanding of giant sellar aneurysms but also provides a foundation for future research to mitigate misdiagnosis and enhance patient quality of life.