From the Guidelines
For a 22-year-old male with gynecomastia, I recommend ordering several key laboratory tests to determine the underlying cause, including testosterone (total and free), estradiol, luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin, thyroid-stimulating hormone (TSH), liver function tests, and human chorionic gonadotropin (hCG) as outlined in the evaluation and management of testosterone deficiency guideline 1.
These tests are essential to identify hormonal imbalances that commonly cause gynecomastia, such as hypogonadism, hyperprolactinemia, or thyroid dysfunction. According to the guideline, serum prolactin should be measured in patients who have low total testosterone and low or low/normal LH levels to screen for hyperprolactinemia 1. Additionally, serum estradiol should be measured in testosterone deficient patients who present with breast symptoms or gynecomastia prior to the commencement of testosterone therapy 1.
Some key points to consider when ordering these tests include:
- Liver and kidney function tests are important because organ dysfunction can alter hormone metabolism
- A thorough medication history should be obtained if medication use is suspected as a cause of gynecomastia
- Additional tests to consider include kidney function tests, a comprehensive metabolic panel, and in some cases, karyotyping if Klinefelter syndrome is suspected
- The patient should be advised that gynecomastia often has an identifiable and treatable cause, and that these tests will guide appropriate management strategies to address both the underlying condition and the breast tissue enlargement.
It's also important to note that most men with breast symptoms can be diagnosed on the basis of clinical findings without imaging, as stated in the acr appropriateness criteria evaluation of the symptomatic male breast 1. However, laboratory tests are necessary to determine the underlying cause of gynecomastia and guide appropriate management.
From the Research
Laboratory Investigations for Gynecomastia
To evaluate gynecomastia in a 22-year-old male, the following laboratory investigations may be considered:
- Testosterone (T) levels 2, 3
- Estradiol (E2) levels 2, 3
- Sex hormone-binding globulin (SHBG) levels 2, 4
- Luteinizing hormone (LH) levels 2
- Follicular stimulating hormone (FSH) levels 2
- Thyroid stimulating hormone (TSH) levels 2, 4
- Prolactin levels 2
- Human chorionic gonadotropin (hCG) levels 2
- Alpha-fetal protein (AFP) levels 2
- Liver and renal function tests 2
Rationale for Laboratory Investigations
These laboratory investigations are recommended to detect underlying pathological conditions, reversible causes, and to discriminate gynecomastia from other breast lumps, particularly breast cancer 2. The presence of gynecomastia can be explained by an imbalance in the ratio of estrogen to androgen tissue levels 3, and thyroid function tests should be examined on initial presentation due to the relative simple treatment of thyrotoxicosis-associated gynecomastia 4.
Additional Evaluations
Additional evaluations, such as breast imaging and testicular ultrasound, may be considered to aid in the diagnosis and management of gynecomastia 2, 3. However, the decision to perform these evaluations should be based on the individual patient's presentation and medical history.