Grave's/Hyperthyroidism and Gynecomastia

[FourT6and2]

Hi there, I'm a 33-year old male recently diagnosed with Grave's Disease—about three months ago. I'm 6' 2", 180lbs. and an active rock climber. So I'm not overweight. I work out 3-5 times a week. No other medical conditions.

Meds: 50mg atenolol, 1/day and 10mg methimazole, 1/day.

My thyroid levels are slowly coming down to normal. I feel great. No lingering symptoms. About 3 weeks into treatment with methimazole I developed gynecomastia in my left nipple. A small 'button' under my nipple, contained within my areola. Had a biopsy to rule out anything bad. But it's gynecomastia.

My endocrinologist says there is no link between gynecomastia and thyroid issues. But that doesn't sound right to me. And I don't think it's a coincidence that it popped up right when I developed Graves'.

Had some blood tests done. Here are the results. My question is: is there anything else I should look at or ask my doctor? Or is it just a hey I have gynecomastia and nothing more can be done. It's no big deal I guess. It isn't physically noticeable to anybody. But it is painful.
I've had routine CBC, calcium, etc. levels as well and they are all normal.

LH: 3.9mIU/mL (1.5 - 9.3)
Estradiol: 30pg/mL (<39)
Prolactin: 6.0ng/mL (2.0 - 18)
FSH: 2.0mIU/mL (1.6 - 8.0)
Total Test.: 756ng/dL (250 - 1,100)
Free Test.: 72.9pg/mL (35 - 155)

[Dr. Schuster]

Hyperthyrodism can definitely cause gynecomastia. Gynecomastia is not listd as a possible side effect of Methimazole, which decreases the formation of thyroid hormone itself. 

[Litlriki]

As noted, there is an association between hyperthyroidism and gynecomastia, which seems to improve when the patient has normal thyroid levels again.  The resolution may take some time, but I'm not sure how long it might take.