PSMA PET/CT Reveals Pituitary Renal Cell Carcinoma Metastasis Mimicking Immune-Related Hypophysitis.

Pituitary metastasis from renal cell carcinoma (RCC) is exceedingly rare and may mimic pituitary macroadenoma. We report a 62-year-old man with a history of RCC and immune checkpoint inhibitor-induced hypothyroidism who presented with persistent headaches and hypopituitarism. PSMA PET/CT revealed intense uptake in a sellar lesion, raising suspicion of metastasis. Histology following transsphenoidal surgery confirmed RCC metastasis. This case underscores the utility of PSMA PET/CT in RCC staging and restaging, especially helpful in detecting atypical metastases, and highlights the challenge of differentiating metastasis from macroadenoma and immunotherapy-related complications.