Question
A 45-year-old man presents with decreased libido and gynecomastia. His serum prolactin is elevated. MRI shows a 2.5 cm pituitary mass. What is the most appropriate first-line treatment?
| A. |
A. Transsphenoidal surgery
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| B. |
B. Radiation therapy
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| C. |
C. Dopamine agonist therapy
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| D. |
D. Observation
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Show Answer
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Correct Answer » C
Explanation
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This patient has a macroprolactinoma (pituitary adenoma >1 cm) causing hyperprolactinemia, as evidenced by decreased libido, gynecomastia, elevated serum prolactin, and a 2.5 cm pituitary mass on MRI.
The first-line treatment for both microprolactinomas and macroprolactinomas is dopamine agonist therapy, with cabergoline being the preferred agent due to its greater efficacy, longer duration of action, and better tolerability. Dopamine agonists suppress prolactin secretion, reduce tumor size, and restore gonadal function.
Why the Other Options Are Incorrect
A. Transsphenoidal resection of the pituitary adenoma
- Surgery is not the initial treatment for prolactinomas.
- It is reserved for patients who are resistant or intolerant to dopamine agonists, those with pituitary apoplexy, cerebrospinal fluid leak, or tumors causing progressive visual compromise despite medical therapy.
B. Radiation therapy
- Radiation is not first-line therapy.
- It is reserved for aggressive or residual tumors that persist despite surgery and medical treatment.
D. Observation with periodic follow-up
- Observation is inappropriate because the patient has a symptomatic macroprolactinoma with endocrine manifestations requiring treatment.
