Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.
A 64-year-old woman is seen for follow-up evaluation. Two weeks ago, she was in a car accident, and an incidental pituitary adenoma was found on a cervical spine CT scan. She has no residual injuries from the car accident.
She is otherwise healthy and takes no medications. She went through menopause at age 51. She has night sweats two to three times per month and occasional hot flushes. These have improved over the past decade and are not bothersome. She is not sexually active. She has never taken hormone replacement therapy. She has had no change in vision, headaches, or galactorrhea.
On physical examination, temperature is 37.5 °C (99.5 °F), blood pressure is 110/63 mm Hg, pulse rate is 82/min, and respiration rate is 14/min. BMI is 26. There is axillary and pubic hair loss. Visual fields are intact. There are no findings suggestive of Cushing syndrome or acromegaly.
Laboratory studies:
| Estradiol | <20 pg/mL (73.4 pmol/L) |
| Follicle-stimulating hormone | 6.4 mU/mL (6.4 U/L) |
| Luteinizing hormone | 3.2 mU/mL (3.2 U/L) |
| Prolactin | 53 ng/mL (53 µg/L) |
| Thyroid-stimulating hormone | 3.2 µU/mL (3.2 mU/L) |
| Thyroxine (T4), free | 1.1 ng/dL (14.2 pmol/L) |
Pituitary MRI shows a 7-mm adenoma in the anterior sella. The tumor is not invasive. It does not approximate the optic chiasm. The pituitary stalk is mid-line.
Which of the following is the most appropriate management?
A: Begin dopamine agonist
B: Gamma knife stereotactic radiosurgery
C: Repeat testing in 12 months
D: Transsphenoidal resection
MKSAP Answer and Critique
The correct answer is C: Repeat testing in 12 months.
No therapy is necessary at this time, and the patient should be retested in 12 months. The patient has a microprolactinoma, but she is postmenopausal. Luteinizing hormone and follicle-stimulating hormone levels are normally high in postmenopausal women because of ovarian failure; however, her levels are lower than expected, likely because the elevated prolactin is providing negative feedback. This causes hypogonadism but is not clinically relevant because she is already hypogonadal from normal menopause. She has minimal symptoms from menopause and is tolerating it well.
The prolactinoma was found incidentally. On MRI, it has no concerning features, and her other pituitary hormone levels are normal. Although no treatment is necessary for this asymptomatic patient, it is advisable to retest in 6 to 12 months to make sure that the tumor does not grow.
Dopamine agonists, such as cabergoline, are used to treat symptomatic prolactinomas, but it is not necessary in this asymptomatic patient.
Radiosurgery is not necessary. It is an option to treat pituitary tumors that are not amenable to standard surgery or cannot be fully resected, but it is not indicated for this asymptomatic patient.
Transsphenoidal resection of the pituitary tumor is overly invasive and unnecessary because she is doing well. In addition, first-line therapy for symptomatic prolactinomas are dopamine agonists, not surgery.
Key Point
- Microprolactinomas in asymptomatic patients do not require treatment; however, surveillance is recommended.
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