The idea is simple: take the whole thing out, plus a border of skin around and beneath it, so nothing abnormal is left behind.
That border is the margin. It exists because tumour cells extend further than the eye can see — a basal cell carcinoma that looks 6 mm across often has roots reaching a few millimetres beyond its visible edge. Margins are set by what is being removed. A benign cyst needs almost none. A basal cell carcinoma is usually taken with about 4 mm. Melanoma margins are set by how deep the tumour grew, ranging from 5 mm for melanoma in situ up to 2 cm for thicker tumours. Wider margins mean higher cure rates and bigger scars, which is the whole trade-off.
The reason the scar is longer than the lesion is geometry, and it surprises almost everyone. If you cut a circle out of skin and pull the sides together, you get a bulge of loose skin at each end — a "dog ear." To avoid that, the circle is extended into an ellipse with pointed ends, at roughly a 3-to-1 length-to-width ratio. So a 1 cm growth with a 4 mm margin all round becomes an 18 mm circle, and the resulting scar is about 5 cm long. That is not a mistake or overtreatment. It is what produces a flat line instead of a puckered lump.
The direction of the ellipse matters too. It is lined up with the natural creases of the skin, because a scar that sits along a crease is far less visible than one crossing it.
Everything removed goes into a pot and to the lab, where the edges are inked and checked. If tumour reaches an edge, more needs to come out.
Excision needs slightly more preparation than the smaller procedures.
Do not stop your blood thinner unless you are specifically told to. Modern practice is to continue aspirin, warfarin, apixaban and similar through minor skin surgery, because the clot risk of stopping is worse than the bleeding risk of continuing. Tell them what you take.
Stop non-essential supplements that thin the blood — fish oil, high-dose vitamin E, ginkgo, garlic tablets — about a week before, if your doctor agrees. These are optional; prescription medication is not.
Stop smoking, ideally two weeks before and two weeks after. Nicotine narrows small blood vessels and is one of the biggest avoidable causes of a wound breaking down.
Tell them about diabetes, immune-suppressing medication, a previous keloid, an artificial joint or heart valve, or a lidocaine allergy.
Eat beforehand, and take your normal medicines.
Wear loose clothing that gives access to the site and that you do not mind marking. If the site is on your leg or back, arrange for a quiet couple of days afterwards.
You do not need to fast or bring a driver — this is done awake under local anaesthetic — but it is reasonable to bring someone if you are anxious.
This is the longest procedure on this list, and almost all of that time is stitching, not cutting.
You lie down. The area is cleaned with antiseptic and the ellipse is drawn on your skin with a surgical pen, lined up with your natural skin creases. Sterile drapes go around it, and the drape over your face if it is a facial lesion is the part some people find claustrophobic — say so and it can be arranged differently.
A fine needle goes in at one end of the drawn ellipse. There is a sharp prick, then a burning, stinging ache for about ten to twenty seconds as the anaesthetic spreads. That burn is the lidocaine itself, which is acidic; buffering or warming it reduces the sting noticeably, and it is fine to ask whether they do that.
Because the area is larger, several injections are made around the ellipse — but after the first one the skin is already numbing, so the rest are barely felt. This is genuinely the worst part of the procedure, it lasts under a minute in total, and everything after it is painless.
You may also notice your heart beating faster for a minute. Local anaesthetic usually contains adrenaline, which reduces bleeding and makes the numbing last longer. The flutter is expected and passes.
The area is tested first — you will be asked whether you can feel a pinch. If you feel anything sharp at any point, say so and more anaesthetic is added. Nobody expects you to tough it out.
What you feel is pressure, tugging, and cool wetness from the antiseptic and from bleeding. No pain. You will hear conversation, the click of instruments, and possibly a short buzz and a smell like burnt hair when small bleeding vessels are sealed with an electric tip. That smell is normal and it is the thing people most often say nobody warned them about.
The lesion and its margin are cut out as an ellipse down to the fat, lifted out, and dropped into a specimen pot.
This is most of the appointment. Dissolving stitches are placed under the skin first — these carry the tension and decide how the scar looks. Then the surface is closed with fine stitches, or occasionally staples or skin glue. You feel pulling and pressure throughout.
A small excision on the back is 20 to 30 minutes. A facial excision or a larger one with a complex closure is 45 to 90 minutes. Add time at the start for consent and marking.
Yes, in almost all cases — you are awake and only the skin is numbed. The exceptions are an excision on your dominant hand, or one on your leg that makes pressing a pedal painful. If you have taken anything for anxiety beforehand, you cannot drive.
The numbness wears off in one to four hours and then it aches. Paracetamol is enough for most people; some need a stronger painkiller for the first night, particularly for the back or the scalp. Keep the dressing on for 24 to 48 hours as instructed.
A little bleeding through the dressing is normal. Press firmly for a full 15 minutes without lifting to check.
Keep the area elevated where you can — a leg up on a stool, an extra pillow for a facial wound — for the first day or two. It reduces swelling and throbbing more than people expect.
Wash gently with soap and water once a day, dry, apply plain petroleum jelly, re-cover. Not antibiotic ointment — it does not lower infection rates on a clean wound and causes an allergic reaction in a fair number of people.
Bruising and swelling peak around day two or three and then improve. Around the eye, bruising can travel down the face and look dramatic.
No swimming, baths, hot tubs or saunas. Showering is usually fine after 24 to 48 hours.
No heavy lifting, no gym, no stretching the area. This is the single most important instruction. A wound on the shoulder, back, chest or knee that gets pulled on in the first two weeks heals into a wide scar, and that is permanent.
Face: 5 to 7 days. Neck: 7 days. Scalp, chest, arms and trunk: 10 to 14 days. Back and legs: 14 days, sometimes longer. Removal takes a couple of minutes and feels like small tugs, not pain. Dissolving stitches under the surface break down over one to three months and occasionally poke through, which is annoying rather than a problem.
The scar goes through its worst-looking phase between weeks three and eight — red, firm, raised, sometimes itchy. This is normal collagen remodelling and it alarms people who assume it is going wrong. Silicone gel or sheeting started once the wound is closed, plus daily sunscreen, gives the best final result.
Red fades to pink, then to pale or slightly darker than the surrounding skin. The scar keeps softening for a year and is not judged before then. On brown and Black skin it more often settles darker rather than paler, and that mark fades over six to twelve months.
Pathology usually comes back in one to two weeks. Ask how you will be told, and call if you have not heard after two weeks.
For skin cancer, this is a treatment with numbers behind it. Excision with adequate margins cures roughly 95 percent of primary basal cell carcinomas and a similar proportion of low-risk squamous cell carcinomas. Early melanoma removed with the correct margin is usually cured by that alone.
If the pathology report says a margin is involved, a second excision is needed to take the rest. That is common enough to be worth expecting rather than fearing, and it does not mean the first operation failed.
For a cyst, complete removal of the sac is curative. Recurrence happens when a fragment of the wall is left, which is more likely if the cyst was inflamed at the time — which is why an angry cyst is usually calmed down first and removed a few weeks later.
For a keloid, excision alone is the wrong plan. Recurrence rates for excision on its own are commonly quoted between 50 and 100 percent, and the regrown keloid is often bigger. Combined with steroid injections, pressure or radiotherapy started immediately after, recurrence drops substantially.
The scar is the permanent result. It is red and firm at six weeks, pink at three months, and close to final at a year. A well-placed excision scar on the trunk or limbs typically ends up a flat pale or faintly darker line. It never disappears, and no cream makes it disappear.
Removing one lesion does not reduce your chance of getting another. Anyone who has had one skin cancer has a substantially raised chance of a second, which is why ongoing skin checks matter more than the operation itself.
There is no home version, and attempting one is where the serious harm on this whole topic sits.
Mole-removal pens, caustic pastes sold as "black salve," wart removers used on growths, cutting something off with nail scissors, and tying a lump off with thread or dental floss are all in circulation. They can appear to work. The lump goes, a scab forms, the skin closes over.
The reason this is dangerous is not mainly the infection or the scar, though both happen often. It is that nobody looked at what was removed. A basal cell carcinoma, an early melanoma and a harmless keratosis can look alike to an untrained eye, and destroying one at home means the tissue is gone and the diagnosis with it. What is left behind under the new scar keeps growing quietly. People arrive years later with something that was straightforward when it started. Black salve in particular burns an unpredictable hole through skin, leaves disfiguring scars, and has repeatedly been documented leaving cancer behind while the surface appeared to heal.
Said once, plainly: do not cut, burn, freeze or tie off a growth at home. If it is worth removing, it is worth knowing what it was.
What you can usefully do at home is everything after the operation. Silicone gel or sheets on the closed scar for at least 12 hours a day over two to three months, daily sunscreen on the scar for a year, and not stretching the area while it heals. Those three things change how the scar ends up more than anything available in a clinic.