Gynecomastia in Men ("Man Boobs"): Gland, Fat, or Something to Have Checked

Medications. Spironolactone, a common blood pressure and heart failure drug, lists enlarged or painful breasts in men among its side effects. Finasteride and dutasteride, taken for prostate enlargement or hair loss, appear on MedlinePlus's list of causes. So do cimetidine, some antidepressants, some antipsychotics, some antibiotics and antifungals, chemotherapy agents, and hormone-blocking or estrogen treatments for prostate cancer. Medications that lower testosterone covers the overlap with the hormone list.

Testosterone therapy and anabolic steroids. Testosterone applied or injected from outside is partly converted to estrogen, and the prescribing information for testosterone gel lists enlarged or painful breasts among its serious side effects. Anabolic steroids do the same. High estradiol in men explains the mechanism.

Alcohol and other substances. Heavy alcohol use, marijuana, heroin, methadone and amphetamines all appear on the standard lists of causes.

Liver disease and kidney failure. A liver that is not working well cannot clear hormones normally, and the American Cancer Society notes that cirrhosis leaves men with a higher ratio of female to male hormones. Kidney failure does something similar.

Thyroid disease. An overactive thyroid is a recognized cause.

Tumors and genetic conditions. A pituitary tumor that makes prolactin, a testicular tumor that makes hCG or estrogen, and Klinefelter syndrome, in which a man carries an extra X chromosome, are the rare causes a workup exists to find.

Topical products. The Endocrine Society lists lavender and tea tree oil products among the causes, so everything applied to the skin counts.

A clinician separates these with a history that covers every drug, supplement and substance, an examination that distinguishes gland from fat and from a cyst, and, where indicated, blood tests and imaging of the breast or testes.

Blood work can identify most of the medical causes above but cannot answer the first question, whether the tissue is gland or fat. That is a physical finding, confirmed where necessary by mammogram or ultrasound.

The markers that inform the cause are total testosterone drawn correctly, in the morning and repeated, because a single afternoon result misleads; getting the test right covers the method. Estradiol, and the balance between the two. LH and FSH, which show whether a low testosterone comes from the testes or from the signal above them. Prolactin, because a prolactin-secreting tumor suppresses that signal. hCG, because a testicular tumor can produce it. Liver and kidney function, and TSH for the thyroid. All of these sit within a baseline panel, and what blood work covers explains each one.

Two cautions. A borderline or low testosterone found during a gynecomastia workup is a finding to explain, not a prescription to write, because testosterone therapy is itself on the list of causes. And most men with gynecomastia have unremarkable blood work, which is the expected result when aging and body fat are the explanation. The testosterone FAQ covers the shorter questions.

ACT 2 Health is a telehealth practice. It does not examine breasts or testes and does not arrange imaging, and any lump in a man's breast is examined in person. Book promptly, within the next week or two, if any of the following applies.

• A hard, fixed or one-sided lump, particularly if it sits off to one side of the nipple rather than centered beneath it. Male breast cancer is uncommon, but it usually presents as a firm, painless lump, and it is more likely in men with Klinefelter syndrome, liver disease, prior estrogen exposure or a family history of breast cancer.
• Nipple discharge or bleeding, a nipple turning inward, or skin over the breast that dimples, puckers, reddens or scales.
• A lump or swelling under the arm or around the collarbone.
• A lump, swelling or heaviness in a testicle, or a testicle that has changed size. Testicular tumors can present through the breast.
• Breast enlargement that is rapid, painful, or new after decades of nothing in a man not on any listed medication.

The most useful minute of the workup is the examination, and it is worth knowing what the examiner is feeling for.

True gynecomastia is a disc of firm or rubbery tissue centered directly beneath the nipple. Cleveland Clinic describes it as a button-sized growth under the nipple that may be tender and moves under the fingers. It is usually on both sides, though not always equally, and pressing toward the nipple meets a distinct edge where the disc begins.

Pseudogynecomastia is fat. It is soft, has no edge, spreads across the chest rather than gathering beneath the nipple, is not tender, and follows the rest of the body.

The third possibility is the one the examination exists to exclude. A cancer is usually hard rather than rubbery, usually on one side, usually painless, and often sits off-center rather than symmetrically beneath the nipple. It may be fixed to the skin or the chest wall. None of those features is reliable enough to rule cancer in or out by hand, which is why a lump with any of them is imaged.

In practice, a man who suspects gland should be examined, because gland has causes worth finding and imaging settles the uncertain cases. A man whose chest is fat has a body composition problem, not a hormonal one. Most men have some of both.