Melanoma in situ means that abnormal melanocytes are found in the outer layer of the skin, or epidermis, says the National Cancer Institute. Melanocytes are the skin cells that give skin its color. Melanoma in situ is not considered cancer but can become cancer and spread.
Fortunately, melanoma in situ is such an early stage of the disease that it is treatable in the doctor's office on an outpatient basis, says the Skin Cancer Foundation. The patient receives local anesthesia, and the abnormal area is simply cut out. The surgeon removes a margin of 0.5 to 1 centimeter of healthy skin and removes the lesion down to the layer of fat. This takes about half an hour for a small lesion. The surgeon sutures the surgical wound, and the resulting scar is usually small.
Mohs microscopic surgery is also a good option for melanoma in situ, says the Skin Cancer Foundation. Mohs surgery is commonly done on squamous and basal cell skin cancers and only recently showed promise in the treatment of some melanomas. In this surgery, the lesion is removed one layer at a time and examined for abnormal cells. When there are no more abnormal cells, the surgery is over.