A 35-year-old man comes to the clinic due to progressive enlargement of his left breast over the past 3 months. He reports no pain, nipple discharge, or family history of breast cancer. The patient has Klinefelter syndrome and is on testosterone replacement therapy. Vital signs are within normal limits. Physical examination reveals a 2.5-cm, firm, non-tender, subareolar mass in the left breast. The right breast is normal. The testes are atrophic, and there is sparse body hair.
Which of the following is the most appropriate next step in management of this patient?
C) Obtain breast imaging
This patient's presentation of a firm, unilateral breast mass raises suspicion for breast cancer, which is more likely in men with Klinefelter syndrome due to the associated increased estrogen-to-androgen ratio. Klinefelter syndrome (KS) is a sex chromosome disorder that occurs when a male has two or more X chromosomes. This can lead to an increased estrogen-to-androgen ratio, which can cause gynecomastia in 30-50% of boys with KS by late puberty. Gynecomastia is a condition that occurs when estradiol levels are elevated. The appropriate next step in management is to obtain breast imaging (mammography) to evaluate the nature of the breast mass.
Answer choice A: Check serum FSH and LH levels, is incorrect. Checking serum FSH and LH levels can help differentiate primary from secondary hypogonadism but is not necessary in this patient with an established diagnosis of Klinefelter syndrome.
Answer choice B: Increase testosterone dose, is incorrect. Increasing testosterone dose may alleviate symptoms of hypogonadism but will not address the primary concern of a potential breast malignancy.
Answer choice D: Prescribe a selective estrogen receptor modulator, is incorrect. Selective estrogen receptor modulators (e.g., tamoxifen) are used in managing gynecomastia and as adjuvant therapy in estrogen receptor-positive breast cancer but should not be initiated before ruling out malignancy.
Answer choice E: Provide reassurance and recommend weight loss, is incorrect. Providing reassurance and recommending weight loss is inappropriate without ruling out malignancy first.
Key Learning Point
In a patient with Klinefelter syndrome presenting with a firm, unilateral breast mass, breast imaging (mammography) should be obtained to evaluate for potential breast cancer, as there is an increased risk associated with higher estrogen-to-androgen ratios in these patients.
