By Dr Ananya Mandal, MD
Skin cancer, skin inflammatory conditions and abnormal growths on the skin are most commonly diagnosed and the diagnosis is confirmed with a biopsy. Biopsy involves removal of a small sample of tissue and examining it under a microscope.
The majority of biopsies performed to diagnose skin cancer involve a minor surgery. This may require local anesthesia and usually does not require hospital stay.
Types of skin biopsy
Tissue from the suspect lesion is surgically removed. There are several types of skin biopsy. Some of these include:
This involves removal of the whole tumor. Sometimes healthy margin around the lesion is also removed. This leaves behind a small wound that may need stitches and dressing. Large biopsies may need a skin graft, or a skin flap to heal rapidly.
This type involves removal of only a part of the lesion. This may be considered when a lesion is large or the location requires maximum preservation of tissue.
Sometimes a core or part of the tissue is scooped out - this is called a punch biopsy. A round needle is used for this type of biopsy.
Minimal bleeding is noted with the 1 mm punch, and often the wound is left to heal without stitching for the smaller punch biopsies. However, these small punches fail to make accurate diagnosis. The common punch size use to diagnose most skin conditions is the 3.5 or 4 mm punch.
The punch biopsy is preferred over the shave biopsy for the diagnosis of skin cancers like squamous cell carcinoma and for melanomas.
Shavings of the tissue from the top may also be removed. This is called a shave biopsy. An incisional biopsy generally is not used to remove a suspected melanoma.
Nail bed biopsy
If skin cancer or melanoma is suspected under the nail bed a nail bed biopsy is performed. During this procedure, part or all of the fingernail or toenail is removed.
Fine Needle Aspiration Biopsy
This is a procedure when a fine needle is used to withdraw a sample of tissue from the lesion. It is rarely used in skin lesions. It may be used commonly to obtain a sample from an internal organ, lymph node, or subcutaneous (beneath the skin) tissue. This is done to determine the possible spread of the cancer.
After a biopsy
Once the sample is removed by biopsy there may be bleeding that is stauched by using electrocautery.
After removal of the tissue the sample of the tissue is cut into microscopic thin slices. This is fixed and stained with special dyes on a glass slide. The slide is then examined under the microscope by a pathologist or a dermatologist (skin specialist) or a pathodermatologists (who specializes in microscopic examinations of skin diseases).
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)
Last Updated: Nov 8, 2012