Gynaecomastia Grades: The Simon Classification and How Your Grade Decides the Technique

Gynaecomastia is usually described by the Simon classification, which grades the male chest by how much enlargement there is and, above all, by whether the skin is stretched: grade I is small enlargement with no excess skin, grade IIa moderate enlargement with no excess skin, grade IIb moderate enlargement with some excess skin, and grade III marked enlargement with clear excess skin, closer to a female breast contour. The grade matters because it decides the operation¹.

When I was first told a “grade”, I heard it as a severity score, a number for how bad my chest was. It is not really that. It is a shorthand a surgeon uses to say how much tissue is there and, more than anything, whether the skin has been stretched, because that one feature changes which operation you are offered. This is the plain version of what the grades mean and why they drive everything else. For the whole picture the grades sit inside, start with the pillar on gynaecomastia surgery.

What is the Simon classification?

The Simon classification is the grading system published by Simon, Hoffman and Kahn in 1973 that sorts gynaecomastia by the degree of enlargement and by whether there is surplus skin, running from grade I through grades IIa and IIb to grade III. It has lasted because the grade maps directly onto the technique¹.

There are other classifications, and reviews note that the many competing systems make it hard to compare studies directly, which is one reason large analyses group results by the surgical approach rather than by grade². But Simon is the one most men will hear at a consultation, and it is worth knowing because it is built around the single question that decides your operation: is the skin stretched or not. Everything below is that one distinction, expanded.

Grade I and IIa: enlargement without excess skin

Grades I and IIa are enlargement of the chest with no excess skin: grade I is a small enlargement and grade IIa a moderate one, and in both the skin is still tight enough to shrink back over a smaller chest once the tissue underneath is removed. These are the grades treated without cutting skin away³.

Because the skin will re-drape itself, these chests are usually handled by taking the fat with liposuction and the firm glandular disc through a small incision hidden at the lower edge of the areola, working through openings only a few millimetres across. That pairing of liposuction for the fat and excision for the gland is the standard for most true gynaecomastia, and it is covered in combined liposuction and excision. The honest point that applies at every grade is that liposuction on its own leaves the gland behind, which is why chests come back around 35% of the time after liposuction only, falling to under 10% once the gland is excised³.

Grade IIb: moderate enlargement with some excess skin

Grade IIb is moderate enlargement with some excess skin: the tissue is comparable to grade IIa, but the skin has been stretched enough that it will not fully tighten back on its own after the tissue is removed. This is the grade where the operation starts to change¹.

Grade IIb is the honest borderline. A surgeon has to judge whether the skin will contract acceptably once the bulk is gone or whether it will sit loose, and that judgement, made by examining and handling the chest, is why you cannot reliably grade yourself. Some IIb chests are treated like the lower grades and given time for the skin to redrape; others cross into needing skin removed. It is the grade that most rewards seeing a surgeon who does a lot of chests and can judge how a stretched skin envelope will behave.

Grade III: marked enlargement with clear excess skin

Grade III is marked enlargement with clear excess skin, a chest closer to a female breast contour, where the skin is plainly surplus and the nipple has usually stretched and dropped. These chests need the skin removed as part of the operation¹.

Grade III is also the common picture after major weight loss, where the fat has gone but a skin envelope is left behind. Here the surplus skin is removed and the nipple resized and repositioned, which is a larger operation and, unavoidably, leaves longer scars than the near-invisible incisions of the lower grades. That trade of a flatter chest for a longer scar is set out in skin removal gynaecomastia surgery, and the scars keep fading for up to a year after the swelling has gone³.

Why the grade decides the technique

The grade decides the technique because it is really a description of what has to be dealt with: grades I to IIa are usually handled by liposuction and gland removal alone through tiny incisions, while grades IIb to III often need skin removal and the nipple repositioned, at the cost of longer scars. The dividing line is excess skin³.

This is the whole reason the grade is worth understanding. It explains why one man is offered an almost scarless operation through a couple of stab incisions and another is offered longer scars and a repositioned nipple: they are not being treated differently for the same problem, they have different amounts of stretched skin. Higher grades can also carry a slightly higher chance of contour or healing issues simply because more tissue and skin are moved: the commonest early problem, a haematoma or collection of blood, is reported at roughly 5.8% in a systematic review, and the leading reasons men need a second procedure are residual firmness, asymmetry, or an over-resected dish under the nipple².

What the grade does not tell you

The grade does not, on its own, separate firm gland from soft fat, and it does not name the cause, so a surgeon assesses those as well as grading the chest. A low grade can be almost pure gland, and a higher grade can be mostly fat and skin⁴.

Mine is the example I know best: on size alone my chest looked minor, an easy low grade, but the fullness was firm gland sitting right behind each nipple rather than fat, which is exactly why two years of lifting never shifted it and why the operation I needed was excision, not just liposuction. The grade told the surgeon how much skin there was; it did not tell him what the lump was. Whether your fullness is gland, fat, or both is the separate question in gynaecomastia versus pseudogynaecomastia, and the cause, from puberty to medicines to anabolic steroids, is reviewed before any cosmetic plan, because a new or one-sided lump is investigated first⁵. Where all of this leaves you as a candidate is set out in am I a candidate for gynaecomastia surgery.