Rare Occurrence of Distant Metastases in Prolactinoma: Insights From 2 Cases and Review of the Literature

Background/Objective: Metastatic PitNETs, formerly called pituitary carcinomas, are rare, accounting for approximately 0.2% of pituitary neoplasms, and prolactin-secreting carcinomas with extracranial metastases are even more uncommon. This report describes 2 patients with prolactin-secreting pituitary carcinomas and extracranial metastases. Case Presentation: Case 1: A 42-year-old woman with secondary amenorrhea was diagnosed with a prolactinoma and treated with dopamine agonists and surgery. Despite high-dose cabergoline and radiotherapy, her prolactin remained elevated. Positron emission tomography Imaging revealed a right iliac lesion, and biopsy confirmed metastatic prolactinoma. She responded to combined focal radiotherapy and temozolomide, with normalization of prolactin and symptom relief. Case 2: A 53-year-old man with a prolactinoma underwent multiple surgeries and medical and radiation treatments over 11 years for progressive tumor growth and prolactin elevation. Imaging revealed widespread skeletal and pleuropulmonary metastases. Despite treatment, he died shortly thereafter. Discussion: These cases highlight the malignant potential of aggressive prolactinomas, and the importance of considering metastases in treatment-resistant cases. Histologic features like elevated Ki-67 and p53 expression can aid diagnosis. Radiotherapy combined with temozolomide may control metastases, though response is variable. Conclusion: These cases emphasize the possibility of extracranial metastasis from prolactinomas, and the challenges in managing treatment-resistant cases, underscoring the need for personalized therapeutic strategies.