Pituitary Gland Metastases As the Initial Presentation of Lung Adenocarcinoma: A Case Report.

Pituitary gland metastases (PMs) are rare and typically asymptomatic, often discovered incidentally in patients with known malignancies. Symptomatic PMs as the initial presentation of cancer are uncommon. We report a case of a 52-year-old woman with no prior oncologic history who presented with progressive unilateral vision loss, headaches, and systemic symptoms. Imaging revealed a sellar and suprasellar mass, and endocrine evaluation indicated both anterior and posterior pituitary dysfunction. Surgical resection and histopathological analysis confirmed metastatic adenocarcinoma of the lung. The patient was treated with radiation to the sellar region and systemic chemoimmunotherapy, resulting in radiologic improvement and partial improvement in vision four months after the initiation of treatment. This case underscores the importance of considering metastatic disease in the differential diagnosis of pituitary masses, particularly in patients with acute neuro-ophthalmologic and endocrine abnormalities. Though difficult to distinguish clinically and radiologically from primary sellar tumors, the presence of diabetes insipidus may indicate a PM diagnosis given its rarity in pituitary adenoma cases. Early recognition and multidisciplinary intervention are critical to improving outcomes and preserving function in such rare and complex presentations.