Wrong Tissue at the Wrong Place: A Rare Case of Hypopituitarism Secondary to Metastatic Renal Cell Carcinoma.

Metastasis to the pituitary gland is a very rare occurrence. The most common primary cancer that metastasizes to the pituitary are breast cancer and lung cancer. Most of the pituitary metastases are asymptomatic. The most commonly reported symptoms include anterior pituitary dysfunction, visual field defects, headaches, and diabetes insipidus. Metastasis from renal cell carcinoma (RCC) is very rare. Here, we present the case of a 59-year-old male who presented with vision changes, fatigue, low libido, a low appetite, and excessive thirst. The hormonal evaluation was consistent with panhypopituitarism, and he was started on hydrocortisone, levothyroxine, testosterone, and desmopressin. Brain MRI showed a suprasellar enhancing mass that progressively increased in size. He underwent endoscopic endonasal transplanum and transtuberculum approach for tumor removal. Biopsy of the tumor was reported as metastatic RCC. He was later scheduled for a gamma knife. Metastatic RCC to pituitary is rare, with most being asymptomatic, leading to a delay in diagnosis. Treatment of pituitary metastases is not standardized and should be tailored to patients' clinical conditions, histology, and the presence of extrapituitary metastases. More prospective studies are needed to formulate guidelines for the management of pituitary metastases.