Endocrine Abstracts

Prolactinomas are the most common secreting pituitary tumors. Although most respond well to dopamine agonists, some prolactinomas are dopamine-resistant and very aggressive. Here we present a 37-year-old patient with aggressive prolactinoma.

Case report: The 37-year-old patient was referred to the University Hospital Centre Zagreb in March 2020 for bilateral visual field defects and headaches due to prolactinoma. In 2017, he had a transsphenoidal resection of the macroprolactinoma. After the surgery, the tumor remnant was 15 mm. The patient was initially treated with bromocriptine and, from October 2019, with cabergoline five times a week. At the first follow-up in our department, the prolactin level was 730 µg/l; MRI showed a residual adenoma of 35x19x22 mm. After one month, the visual field further deteriorated, and the prolactin level increased to 1270 µg/l. The patient was sent for transcranial surgery. The postoperative prolactin level was 644 µg/l. After discharge, he was treated with cabergoline. In May, he was readmitted for visual field disturbances and a prolactin level of 1955 µg/l. MRI showed tumor progression. The patient underwent further transsphenoidal tumor resection and was referred for concomitant chemoradiotherapy (temozolomide + conventional radiotherapy) followed by nine cycles of temozolomide. In the next seven months, MRI showed regression of the tumor and reduction of prolactin levels to 28 mg/l. From July to November 2021, the prolactin level gradually increased to 705 µg/l. MRI scan again showed tumor progression. He was treated with cabergoline and anastrozole and restarted temozolomide until he was hospitalized due to a COVID-19 infection. In January, another transcranial surgery was performed. The PRL level after the surgery was 1640 mg/l, and an MRI scan showed a residual tumor. Pasireotide therapy was initiated, and he received three applications. The PRL level further increased to 3030 mg/l in April 2022. It was decided to start bevacizumab, but the patient developed sepsis and died before bevacizumab could be started.

Conclusion: This aggressive prolactinoma did not respond to many treatment modalities. Unfortunately, immune checkpoint inhibitors are mainly unattainable due to their cost.