Moles (nevi) are common, benign skin growths formed when pigment-producing cells (melanocytes) cluster together. Most people have between 10 and 40 moles, which are typically acquired during childhood and adolescence. They usually appear as small, uniform spots that are brown, tan, or flesh-colored. Understanding the characteristics of a normal mole is key to maintaining skin health.
Identifying Moles That Need Attention
Regular self-examination is an important early detection measure for tracking changing spots. You should look for visual characteristics that suggest a mole has become suspicious, using a guide known as the ABCDE method. This mnemonic helps identify features that are generally absent in harmless moles but often present in melanoma.
Asymmetry (A)
A stands for Asymmetry, where one half of the mole does not match the other half in shape or size. Benign moles are usually symmetrical, allowing a line drawn through the middle to create two equal halves.
Border Irregularity (B)
B refers to Border irregularity, meaning the edges of the mole are ragged, notched, blurred, or scalloped rather than smooth and well-defined.
Color Variation (C)
C highlights Color variation, indicating the presence of multiple shades within the same lesion. A harmless mole is typically one uniform color, but a suspicious one may contain shades of brown, tan, and black, sometimes mixed with red, white, or blue.
Diameter (D)
D stands for Diameter, suggesting that a mole larger than about six millimeters, roughly the size of a pencil eraser, warrants professional evaluation. Some melanomas can be smaller than this at the time of detection.
Evolving (E)
E represents Evolving, which refers to any noticeable change in the mole’s size, shape, color, or elevation over time. Other signs include a mole that begins to itch, bleed, or crust over, or one that looks substantially different from other spots. If you observe any of these changes, seeking professional advice is the appropriate next step.
Clinical Assessment and Monitoring
When a mole exhibits suspicious characteristics, a dermatologist performs a thorough skin examination. The physician often uses a specialized, handheld instrument called a dermatoscope to enhance the assessment. This non-invasive tool provides magnification and a light source, allowing visualization of structures and pigment patterns beneath the skin’s surface. By analyzing these subsurface features, the doctor can better differentiate between a harmless nevus and a potentially malignant lesion.
If the dermoscopic examination does not provide a definitive diagnosis, a biopsy is performed to obtain a tissue sample for laboratory analysis. This quick, in-office procedure begins with the injection of a local anesthetic to numb the area completely.
Biopsy Types
One common method is a shave biopsy, where a blade removes only the superficial, raised portion of the mole, often used for lesions confined to the skin’s upper layers. For moles that are flatter, deeper, or highly suspicious for melanoma, a full-thickness sample is necessary to accurately measure the lesion’s depth. This is accomplished with either a punch biopsy, which removes a cylindrical section of skin, or an excisional biopsy, which removes the entire mole plus a small margin of surrounding healthy skin. The tissue sample is then sent to a pathologist who examines the cells under a microscope to confirm a diagnosis.
Active Monitoring
For patients with numerous atypical but benign moles, the dermatologist may recommend active monitoring. This involves routine follow-up appointments, often every four to six months, to track the moles over time. Digital tools, such as total-body photography and digital dermoscopy, are sometimes used to create a baseline record, making it easier to detect subtle changes in appearance at subsequent visits.
Methods for Mole Removal
Mole removal procedures are performed for medical necessity, such as confirmed or suspected skin cancer, or for cosmetic purposes, when a mole causes irritation or distress. The choice of technique depends on the mole’s size, its depth in the skin, and the medical need for a complete tissue sample. Both shave excision and surgical excision are commonly employed, each offering distinct advantages and recovery profiles.
Shave Excision
Shave excision is the preferred method for removing moles that are raised above the skin’s surface and are presumed to be benign. After the area is numbed with a local anesthetic, a specialized blade is used to horizontally slice the mole off at skin level. This technique is fast, does not require stitches, and typically leaves a minimal scar that heals as a small, flat mark, making it a desirable option for cosmetically sensitive areas.
However, because shave excision only removes the portion of the mole above the deeper layers of skin, there is a possibility that some pigment cells may remain, which could result in the mole regrowing over time. This technique is not used for suspected melanomas, as it may not provide the pathologist with the necessary deep tissue margin to accurately stage the cancer.
Surgical Excision
Surgical excision, a more involved procedure, is typically reserved for moles that are flat, have deeper roots, or are highly suspicious for malignancy. The entire mole is cut out using a scalpel, along with a narrow margin of surrounding tissue to ensure complete removal of any abnormal cells. The resulting elliptical wound must then be closed with sutures, which leaves a thin, linear scar that usually fades over several months.
Recovery from a surgical excision is longer than from a shave procedure, often requiring patients to limit strenuous activity for a period of one to two weeks to allow the wound to heal. This method provides the most comprehensive tissue sample for diagnosis and offers the lowest chance of mole recurrence, making it the standard approach when cancer is a possibility.