6534 Schwannoma-Induced Hyperprolactinemia: A Rare Presentation Unveiled

Abstract Disclosure: G. Naronowicz: None. F.F. Foo: None. J. Cheng: None. R. Ong: None. S.W. Holland: None. K. Chalasani: None. Background: This case describes a rare presentation of a schwannoma manifesting with hyperprolactinemia. Case Description: A 37 year-old female with a past medical history including prolactinoma presented to our endocrine office to establish care. Prior to presentation, this patient had been diagnosed with a prolactinoma in 2015 via MRI. She was started on Cabergoline 0.5mg twice a week for treatment and continued this medication without any bothersome side effects. However, she began experiencing progressive dizziness, tinnitus, bilateral galactorrhea, and vision changes, prompting her to seek further intervention. The patient presented to our endocrine office in October 2017 for her initial visit. Due to ongoing symptoms, an MRI was done which revealed an adenoma vs hyperplasia of the pituitary gland. During this time her prolactin level was within normal limits, thus she continued her Cabergoline regimen. Soon thereafter, the patient was seen again in April 2018 with evidence of stable prolactin levels on Cabergoline treatment, although a repeat MRI showed a concern for a 1.2 cm mass in the left cerebellopontine angle extending to the right auditory canal. The patient underwent a follow-up consultation with a neurosurgeon; However given the unavailability of surgery at that time owing to insurance-related matters, a subsequent MRI was performed in August 2019 which revealed a vestibular schwannoma with no pituitary mass, and she ultimately underwent resection of this mass in February 2020. Throughout this period, the patient presented with a rise in prolactin levels (23.7 to 41.9 ng/mL). However, due to an asymptomatic state and the absence of concerning pituitary mass, the decision to be observed off Cabergoline therapy appeared to be the appropriate clinical course of action. Following the surgery, she was seen again in June 2020 with normalization of her prolactin levels without ongoing cabergoline treatment. We continue to follow this patient to present day for annual appointments and she continues to have normal prolactin levels. Conclusion: This report underlines the importance of a thorough and multidisciplinary approach in the assessment of elevated prolactin levels in light of a schwannoma. This also highlights the significance of continued surveillance and the value of repeat imaging. Exploring alternative diagnoses, such as Schwannoma, broadens the scope of etiologies, thus allowing a comprehensive approach for accurate diagnosis. Presentation: 6/1/2024