Skin biopsy
A biopsy removes a small sample of skin so that it can be examined under the microscope. It is the most reliable way to confirm or rule out a diagnosis when the appearance alone is not enough, and it is done in clinic in a few minutes. The area is cleaned and numbed with a local anaesthetic injection, which stings briefly. After that you should feel pressure but not pain.
Shave biopsy
A thin blade removes the raised part of a lesion at or just below the surface of the skin. No stitches are needed. The wound heals from the base over one to two weeks and usually leaves a flat, pale mark. Shave biopsy suits raised growths and lesions where a surface sample is enough for diagnosis.
Punch biopsy
A small round instrument, usually three to four millimetres across, removes a full thickness core of skin. The wound is closed with one or two stitches, removed after one to two weeks depending on the site. Punch biopsy is used for rashes and for lesions where the deeper layers of skin need to be seen.
Excisional biopsy
The whole lesion is removed with a narrow margin of normal skin, as an ellipse, and the wound is closed with stitches. This is used when a lesion may be a melanoma or another cancer, because it allows the pathologist to examine the entire lesion and its edges. It leaves a straight line scar somewhat longer than the lesion itself.
Excision of skin cancers and suspicious lesions
Basal cell carcinoma, squamous cell carcinoma and early melanoma are most often treated by surgical excision. The lesion is removed with a margin of surrounding skin sized to the type of cancer, and the wound is closed with stitches. Larger wounds may need a flap or a graft, and some sites or cancers are referred on to a surgical specialist. The removed tissue is examined to confirm that the margins are clear. If they are not, a second procedure is arranged.
Most excisions take between twenty and forty five minutes. You are awake throughout and can go home afterwards. Arrange for someone to drive you if the procedure is on the face or if you are anxious about it.
Cryotherapy
Cryotherapy freezes a lesion with liquid nitrogen, applied as a spray or with a cotton tip, for a few seconds. It is used for actinic keratoses, warts, seborrhoeic keratoses causing symptoms, and some other benign or precancerous growths. The area stings during treatment and for a few minutes afterwards, then becomes red and may blister within a day. The treated skin peels off over one to two weeks. Some lesions need more than one treatment. Cryotherapy can leave a pale mark, particularly on darker skin, and this is discussed before treatment.
What to expect on the day
Before
Eat normally. Take your usual medications unless told otherwise. Tell us in advance about blood thinners, a pacemaker or defibrillator, allergies to local anaesthetic or dressings, and any history of poor healing or keloid scarring. Most procedures go ahead on blood thinners with extra care.
During
The site is marked, cleaned and numbed. You may feel tugging or pressure. The procedure itself is usually short. A dressing is applied and you are given written wound care instructions before you leave.
After
Some soreness for a day or two is normal and responds to acetaminophen. Bruising and mild swelling are common on the face. Keep the dressing dry for the first day, then follow the wound care instructions below. Return for stitch removal if a date has been given.
Wound care
- Leave the first dressing in place for 24 hours unless told otherwise.
- Clean the wound once or twice a day with soap and water or saline. Pat dry.
- Apply a thin layer of petroleum jelly and cover with a fresh non stick dressing. A moist, covered wound heals faster and scars less than one left to dry out.
- Avoid heavy lifting, stretching the area or swimming until stitches are out and the wound has closed.
- Some oozing or a little bleeding is normal. Press firmly with clean gauze for ten minutes. If bleeding does not stop, call the clinic.
- Call if the wound becomes increasingly red, hot, swollen or painful, if there is pus, or if you develop a fever. These can be signs of infection.
- Once healed, protect the scar from the sun for at least a year. Scars fade over six to twelve months.
Results
Biopsy and excision specimens are examined in house by a physician certified in both Dermatology and Anatomical Pathology. Typical turnaround for results is being confirmed. Results are sent to your referring physician, and where a result changes the plan or requires further treatment our office contacts you directly to arrange a follow up visit. If you have not heard anything and are concerned, call 905 625 5600.
Cosmetic removal is not covered by OHIP
Removal of a benign lesion, such as a harmless mole, skin tag or seborrhoeic keratosis, for cosmetic reasons alone is not an insured service in Ontario. Where a lesion is suspicious, symptomatic or interfering with function, assessment and treatment are covered. If you ask for a benign lesion to be removed for appearance, the fee is explained before anything is done. See private services.
For referring physicians
Please describe the site, size and duration of the lesion, any change in size, colour or shape, any bleeding or ulceration, and the patient's history of skin cancer, immunosuppression and anticoagulation. An image attached to the referral helps triage. Suspected melanoma should be flagged as urgent. How to refer.