Abstract
BACKGROUND: Pituitary metastases are rare, accounting for only 1% of all pituitary tumor resections. Prostate adenocarcinoma, a common malignancy in men, seldom metastasizes to the pituitary gland, with only a few reported cases. Given their rarity and non-specific clinical presentation, pituitary metastases are often mistaken for primary sellar lesions. Advanced imaging techniques, including Prostate-Specific Membrane Antigen (PSMA) positron emission tomography (PET)/Computed Tomography (CT) and molecular diagnostics, such as DNA methylation profiling, can aid in accurate diagnosis and differentiation from pituitary adenomas. CASE PRESENTATION: We report the case of a 71-year-old male with a history of prostate adenocarcinoma who presented with biochemical recurrence and underwent PSMA PET/CT imaging, revealing intense tracer uptake in the pituitary gland. Magnetic Resonance Imaging (MRI) findings were suggestive of a pituitary macroadenoma, and the patient developed bitemporal hemianopia, necessitating transsphenoidal surgical resection. Histopathological and immunohistochemical analyses were not compatible with a primary pituitary lesion, prompting further investigation via DNA methylation profiling. The analysis revealed a DNA-methylation signature consistent with prostate carcinoma, confirming pituitary metastasis. The patient subsequently received systemic treatment with androgen deprivation therapy, abiraterone, and docetaxel, achieving an excellent biochemical and imaging response. CONCLUSION: This case highlights the importance of considering metastatic prostate cancer in the differential diagnosis of pituitary lesions, particularly when PSMA PET/CT shows focal uptake in atypical locations. Integration of histopathological, immunohistochemical, and molecular techniques, such as DNA-methylation profiling, was essential for confirming the diagnosis. Clinicians should remain vigilant for atypical metastatic presentations and leverage advanced diagnostic tools to ensure accurate diagnosis and optimal patient management.