SAT-126 - An Aggressive Giant Prolactinoma Refractory to Multimodal Therapy: A Case Report with Fatal Postoperative Cerebral Infarction

Giant prolactinomas are characterized by size > 4 cm, prolactin > 1000 ng/ml, and symptoms of hyperprolactinemia or mass effect. They are rare making up to 2 – 3% of all prolactin secreting tumors. Aggressive prolactinoma are even rarer, representing ~10% of pituitary tumors and exhibit 3 main features: tumor invasion based on radiological/histological features, a higher proliferation profile, and aggressive behavior like rapidly developing, resistance to standard medications, and increased risk of early recurrence despite standard therapies combining medical and surgical approaches. Management requires a complex multidisciplinary approach including surgery, dopamine agonist, radiotherapy and occasionally temozolomide, an alkylating agent. We report a case of an aggressive giant prolactinoma refractory to multimodal therapy, complicated by fatal postoperative stroke.
A 53-year-old woman with a history of prolactinoma diagnosed three years earlier presented with vision loss and altered mentation. Initial imaging showed a 4.1 × 3.1 × 2.2 cm sellar mass compressing the optic chiasm, and prolactin >2000 ng/mL. She underwent transsphenoidal resection and revision craniotomy in April 2022, developing hypothyroidism and adrenal insufficiency postoperatively, managed with levothyroxine and hydrocortisone. She was discharged on cabergoline 0.5 mg thrice weekly. On current admission, MRI revealed an enlarged sellar/suprasellar mass measuring 5.6 × 3.1 × 2.7 cm with hypothalamic and ventricular compression. Prolactin was markedly elevated at 7,245 ng/mL, measured by serial dilution. She underwent repeat transsphenoidal hypophysectomy, followed by debulking craniotomy five days later. Histopathology showed extensive fibrosis, high mitotic activity (8/10 HPF), and Ki-67 index of 4–5%. Postoperatively, she developed ischemic infarction in the right basal ganglia and anterior cerebral artery territory with cerebral edema and worsening midline shift. Despite maximal medical management, neurological decline progressed, and after family discussion, she was transitioned to hospice and died shortly after extubation.
Our case demonstrates the potentially aggressive nature of invasive giant prolactinomas and is also remarkable for the severity and rare sequela that complicated the patient's clinical course, highlighting the potential for catastrophic postoperative complications. Aggressive giant prolactinoma is a challenging clinical scenario, and in such cases where treatment is limited, multidisciplinary collaboration is crucial for a holistic approach and achieving optimal therapeutic outcomes for the patient.

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