SAT-129 - Long-Term Stability of an Untreated Asymptomatic Macroprolactinoma: A Case for Conservative Management

Introduction: Prolactinomas are the most common pituitary adenomas. Although current guidelines recommend treatment of all macroprolactinomas given the risk of neurologic compromise and progressive endocrine dysfunction, the need for routine therapy in stable, asymptomatic lesions remains uncertain. This ambiguity highlights the need for more robust data to guide management.

Case Presentation: A 79-year-old woman presented after a fall resulting in a 5-mm acute subdural hematoma on noncontrast computed tomography (CT) of the head. Magnetic resonance imaging (MRI) of the brain performed during the admission incidentally revealed a 1.8 × 1.8 × 1.7 cm pituitary adenoma. Review of prior records identified a pituitary macroadenoma discovered in 2015, measuring 2.2 × 1.8 × 2.2 cm, for which she had never received evaluation or treatment. She had remained asymptomatic from the lesion for approximately 10 years. Laboratory evaluation during the admission showed a markedly elevated serum prolactin level of 938.7 ng/mL (reference range, 2.8–29.2 ng/mL) with suppressed gonadotropins (luteinizing hormone < 0.1 mIU/mL; follicle-stimulating hormone 0.4 mIU/mL). Thyrotropin was 2.130 µIU/mL, insulin-like growth factor 1 was 117 ng/mL, and adrenocorticotropic hormone was 27.6 pg/mL, all within their respective reference ranges. Serum cortisol was elevated at 24 µg/dL, likely reflecting an acute stress response to trauma. Visual fields were intact bilaterally. Given her lack of symptoms and a preference to avoid additional medications, the patient declined dopamine agonist therapy to minimize medication burden.

Discussion: This case illustrates the long-term stability of an untreated macroprolactinoma in an asymptomatic postmenopausal woman. Despite marked hyperprolactinemia and suppressed gonadotropins, the tumor remained radiographically stable for a decade without therapy. These findings challenge current recommendations favoring treatment of all macroprolactinomas, irrespective of symptoms, and highlight the need for additional data to inform whether a more individualized approach to management may be warranted.

Conclusion: Asymptomatic macroprolactinomas may not always necessitate immediate treatment. This case supports an observation-based approach in a postmenopausal patient with a stable, nonprogressive macroprolactinoma, challenging current assumptions, and highlighting the need for further research.

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