Surgical margins should be clear for a severely dysplastic nevus
Dysplastic nevi are atypical "funny looking" moles that are often categorized as having mild, moderate or severe atypia. They are generally larger and darker than other moles and have irregular or indistinct borders. When an abnormal mole is identified, a shave or punch biopsy is often performed for diagnosis. If the dysplastic nevus is classifed as severe, I often recommend a 5mm clear margin. In my experience, it is often difficult to clinically and pathologically distinguish these lesions from melanoma in situ.
A mole with severe dysplasia
The lesion needs to be excised such that there are microsopically clear margins. Punch biopsy or elliptical excision are both acceptable methods of excision as long as the margins are clear.
Removal with Clinically and Microscopically Clear Margins Important
Atypical Nevi (moles) that are severely or moderately atypical need to be completely excised both clinically and microscopically. Midly atypical nevi (sometimes called a Clark's Nevus) are considered, by most dermatologist, to be a variant of normal, and complete re-excision is not necessary.
A Biopsy Punch is really a tool that is generally used to obtain a diagnosis (biopsy) but this tool may also be used for treatment (excision). Some Biopsy punches are large enough to encircle the entire lesion along with the necessary margin for clearance. If the lesion is completely removed with adequate microscopic margins, you should be fine.
One thing to keep in mind-- the science of pigmented lesions is imperfect. There is great debate within the scientific community about exactly what an atypical mole really means, about the necessity to treat and what the proper treatment is. Be sure to consult with a respected, Board Certified Dermatologist that you trust and have a good rapport. This is the best way to obtain your best care.
A severely dysplastic mole is very close to melanoma.
A punch biopsy is enough only if it is VERY small. A severely dysplastic mole is very close to melanoma. I usually take at least a few millimeters margin to ensure the surrounding tissue is clear. The pathology report should show how close the lesion was to the margin. If it was close, I would recommend re-excision.
Margins for atypical moles
I think it is important to get clinically clear margins (both visually and microscopically) when removing a biopsy-proven atypical mole. It's best not to get hung up over measurements in millimeters as these are only guidelines. In my office, we will do an excision with suture closure to get clear margins for all moles that have moderate to severe atypia. For a mildly atypical mole we will observe the area and, if any pigmentation recurs in the biopsy site in the future, a very small excision is done (often with a small punch biopsy tool) for a minimal scar. We also follow all of our "atypical mole" patients by doing full skin examinations every six months.
I don't think you need to be too concerned. Where were these moles would be my first question? Second, margins are used as guidelines. If the mole was tiny, a 3mm margin could have been just fine and a 5mm margin could have been excessive. Usually we take larger margins on places like the body (trunk, arms, legs) where the skin is a bit more forgiving and we take as minimal as possible on the face and hands, where there isn't a lot of skin to give. I don't even do punch biopsies because I find often that they go too wide and deep and remove too much skin unnecessarily which can lead to scars and marks. I always use a scalpel when doing mole removals. If you see something return in the area, you need to have it looked at, but don't worry about margin sizes.