A 46-year-old African-American male has a large pituitary mass, which was seen on a CT scan of his head following a head injury. He denies any symptoms, except for mild erectile impotence. Physical examination reveals a right, upper, temporal, quadrantic field defect. His hormonal profile shows a prolactin level of 5,000 ng/mL (normal 5-20 ng/ml). His IGF-1, TSH, and free T4 levels are normal, while his LH and FSH levels are low. MRI reveals a 2.5 cm pituitary mass abutting, but not elevating, the optic chiasm. What is the most appropriate management for this patient?

Question

A 46-year-old African-American male has a large pituitary mass, which was seen on a CT scan of his head following a head injury.  He denies any symptoms, except for mild erectile impotence.  Physical examination reveals a right, upper, temporal, quadrantic field defect.  His hormonal profile shows a prolactin level of 5,000 ng/mL (normal 5-20 ng/ml).  His IGF-1, TSH, and free T4 levels are normal, while his LH and FSH levels are low.  MRI reveals a 2.5 cm pituitary mass abutting, but not elevating, the optic chiasm.  What is the most appropriate management for this patient?

Quizplus · Accepted Answer

Explanation: The patient has a large macroadenoma that is likely to respond to oral dopaminergic receptor agonists. Dopaminergic receptor agonists (bromocriptine and cabergoline) are the first-line treatment for prolactinomas, including large prolactinomas. With such treatment, the tumor's size decreases within days, and the patient's vision improves even before the decrease in tumor size is appreciated on MRI. Once treatment with an agent is started, the patient will require close monitoring of his clinical symptoms, prolactin levels, visual field assessments, and MRI of his pituitary gland. (Choices A and B) Transphenoidal and transcranial surgery is rarely required for patients with prolactinomas. Even patients with visual defects or other compressive symptoms may respond to treatment with dopaminergic receptor agonists. (Choice C) Hypogonadism secondary to hyperprolactinemia is likely to respond to dopaminergic receptor agonists. Treatment with testosterone is not warranted at this time. (Choice D)Gamma knife radiation is contraindicated in this patient because the tumor is within 5 mm of the optic chiasm. Furthermore, gamma knife is not indicated as a primary mode of treatment in majority of patients with pituitary tumor because of the lack of immediate effects and an increased risk of hypopituitarism in the long term. Educational Objective: Dopaminergic receptor agonists are first-line treatment for prolactinomas, including large prolactinomas. Treatment with dopaminergic receptor agonists generally leads to a decrease in tumor size within a few days. Visual symptoms usually improve before the tumor's decrease in size is seen on MRI.

A 46-Year-Old African-American Male Has a Large Pituitary Mass, Which Was