Fellow University of Mississippi Medical Center Flowood, Mississippi, United States
Introduction : The standard of care for prolactinomas is pharmaceutical therapy with dopamine receptor agonists such as cabergoline. Long term pharmacotherapy is typically required. This can create a challenge in the setting of schizophrenia where dopamine receptor antagonism is the standard of care. To explore this challenge, we describe a case where a patient with schizophrenia is found to have a giant prolactinoma with cabergoline resistance.
Case(s) Description : Our patient is a 67 year old female with type 2 diabetes, hypertension, and schizophrenia treated with quetiapine that developed an unsteady gait resulting in multiple falls over a two week period. Imaging discovered a 5 cm pituitary mass with suprasellar extension and evidence of hemorrhage. Her laboratory work up was significant for a prolactin greater than 4,700. Initial management was thoroughly discussed. Her schizophrenia had been well controlled and it was decided to start a trial of cabergoline 1 mg twice weekly. At her 4 week follow up visit, prolactin remained greater than 4,700. She reported no side effects from cabergoline or worsening of her schizophrenia, and cabergoline was increased to 2 mg twice weekly. Unfortunately over the next few months, she experienced significant cognitive decline. She was unable to travel or complete any activities of daily living without assistance. Follow up MRI showed no reduction in size of the mass and demonstrated elevation of the optic chiasm and third ventricle. Given her poor response to cabergoline, current need for dopamine antagonism, and severe cognitive decline including visual disturbances, it was decided to pursue surgical debulking of the tumor. Transsphenoidal resection and craniotomy were completed with complications of central diabetes insipidus and secondary adrenal insufficiency. Pathology was not consistent with malignancy. She did have significant improvement in her cognition and prolactin decreased from 2,330 to 476. She was continued on cabergoline at discharge. Her post-op course was notable for continued headaches, visual disturbances, and hydrocephalus that required ventricular shunt placement. Prolactin continues to decline but has yet to normalize.
Discussion : There remains no clear guidance for schizophrenic patients with prolactinomas, and management requires case-based clinical judgement. Even though it is well known that dopamine agonists can exacerbate schizophrenia, there are several cases described where patients were able to tolerate cabergoline with combination mirtazapine and quetiapine. We also observed this in our case. Surgical resection remains an option for resistant prolactinomas defined as a lack of decrease in tumor size by 50% and a failure to normalize prolactin. Surgery can result in lifelong complications and is usually reserved for cases of aggressive growth, tumor bleeding, or severe symptoms of mass effect. Recurrence rates for macroadenomas are around 22% therefore continuation of dopamine agonist therapy is important if tolerated. If surgery cannot stabilize the tumor, radiation therapy can be considered.
