Pituitary Metastasis from a High Grade Serous Ovarian Carcinoma Presenting as Hyponatremia with Masked Diabetes Insipidus: A Case Report

Pituitary metastasis is a rare entity, with majority of the primary tumors reported from breast or lung origins. We present a case with pituitary metastasis as the first clinical presentation of underlying ovarian carcinoma. A 48-year-old female presented with visual disturbances and hyponatremic episodes. After management of her hyponatremia and resulting diabetes insipidus, detailed imaging was carried out which revealed a 35 mm x 35 mm x 20 mm (TS x CC x AP) pituitary mass, extending into the cavernous sinuses and suprasellar compartment, causing compression of the optic chiasma. Debulking was performed via the endoscopic trans-sphenoidal approach, and biopsy was consistent with metastatic high-grade ovarian serous carcinoma (WT1+ and estrogen receptor+). A CT chest-abdomen-pelvis revealed a 10 cm right ovarian mass with bilateral adrenal nodules. Postoperatively, patient developed CSF rhinorrhea and meningitis. Despite, reconstructive efforts, the patient continued to decline and was referred to palliation. She succumbed to her illness during her hospital admission. Our case underscores the importance of considering pituitary metastasis when encountering DI or pituitary insufficiency in a middle-aged patient with a sellar mass.