All moles are made up of collections of the pigment-producing cells of the skin; they may be flat, raised, skin-colored, or pinker or darker than the skin. Atypical moles are characterized by having abnormal cell growth, but this is not always obvious from looking at the mole, and a doctor may have to biopsy the mole and look at a portion of it under a microscope to make this diagnosis.
It is important to show all your moles particularly those that are new or rapidly changing to your doctor because these atypical nevi are sometimes considered an early form of cancer. Anyone can develop atypical moles.
In general, moles are more common and also more noticeable in lighter-skinned people. Those with a family history and those with a lot of sun or tanning bed exposure are at increased risk of developing atypical moles. Atypical moles may appear anywhere on the skin.
They can be larger than a pencil eraser 6 mm and may have variations in color within the lesion ranging from pink to reddish-brown to dark brown. Atypical moles may be darker brown in the center or on the edges periphery. People with atypical-nevus syndrome may have hundreds of moles of varying sizes and colors. Any atypical mole that does not belong to the predominant type in an individual patient should be given special attention. The primary purpose of biopsy in atypical moles is to rule out melanoma.
With nearly 80 percent of melanomas arising de novo on skin without a mole , only changing or new moles with clinical features that are worrisome for melanoma need to be biopsied. The physician must decide between incisional biopsy using superficial shave, deep shave, or punch techniques and excisional biopsy Table 3. In a prospective cohort study of adults who each had five or more atypical moles, 20 new melanomas were detected in 16 patients during an average of 42 months' follow-up.
Eleven of these lesions were discovered because of change in pigmented lesions compared with baseline photographs and the other nine lesions were discovered by the patients or their partners. Thirteen of the 20 melanomas arose from new lesions, and only three from existing atypical moles. The authors concluded that if all atypical moles in the patients were removed almost 6, moles , only three melanomas would have been prevented.
A thick disk of tissue is removed by a curved blade; sample extends to at least mid dermis 1 to 4 mm in depth. A disk of tissue is removed by skin punch instrument 4 to 8 mm punch ; sample is cylindrical. Information from reference Excisional biopsy provides the pathologist with optimal tissue for histologic diagnosis, and deep shave biopsy provides adequate tissue for histologic assessment in about 88 percent of cases.
Deep shave biopsy is quicker, less expensive, less scarring, and has fewer complications, but lesions may recur at a rate three times higher than with excision. Nevertheless, in a retrospective study of persons with melanoma, 88 percent of initial shave and punch biopsies were accurate, with Breslow depth greater than or equal to the Breslow depth in subsequent excision.
Superficial and deep shave biopsies were more accurate than punch biopsies for melanomas less than 1 mm in diameter, and excisional biopsy was the most accurate biopsy method. If the decision has been made to completely remove an atypical mole, a 2-mm specimen margin is important to avoid the need for reexcision. Residual moles were more common in lesions removed by punch biopsy than those removed by shave biopsy or elliptical excision.
In a study of the value of reexcision in atypical moles, only 25 percent of the reexcised lesions contained residual mole cells, and only one of the lesions contained melanoma. Because most melanomas arise on normal skin and because most atypical moles do not progress to melanoma, reexcision of most lesions is probably unnecessary unless lesions show moderate to severe architectural disorder or moderate to severe cytologic atypia.
Physicians who biopsy and follow atypical moles should send the specimens to a dermatopathologist with experience in the interpretation of complex pigmented lesions. Referral to a dermatologist should be considered in patients with multiple atypical moles, depending on the physician's comfort level with monitoring and biopsying these lesions. Already a member or subscriber?
Log in. Interested in AAFP membership? Learn more. She received her medical degree from the University of Vermont College of Medicine in Burlington, and completed a family medicine residency at Maine Medical Center. Address correspondence to Peggy R. Cyr, MD, 22 Bramhall St. Reprints are not available from the author. The author thanks Lisa Kay Moore for her assistance in the preparation of the manuscript.
Figure 5 courtesy of Carrine Burns, MD. Origin of familial malignant melanomas from heritable melanocytic lesions. Precursor lesions in familial melanoma. A new genetic preneoplastic syndrome. Salopek TG. The dilemma of the dysplastic nevus. Dermatol Clin. NIH Consensus conference. Diagnosis and treatment of early melanoma. Atypical mole syndrome: risk factors for cutaneous malignant melanoma and implications for management. J Am Acad Dermatol. Excess of nevi related to immunodeficiency: a study in HIV-infected patients and renal transplant recipients.
J Invest Dermatol. Cancer statistics, CA Cancer J Clin. Cutaneous melanoma: update on prevention, screening, diagnosis, and treatment. Am Fam Physician. A case-control study. Arch Dermatol. Prevention and early detection of malignant melanoma. Fernandez E, Helm K. The diameter of melanomas. Dermatol Surg.
Diagnosis and management of malignant melanoma [published correction appears in Am Fam Physician. Tsao H, Sober AJ. Atypical melanocytic nevi. Fitzpatrick's Dermatology in General Medicine. Naeyaert JM, Brochez L. Clinical practice. Dysplastic nevi. N Engl J Med. The early and intermediate precursor lesions of tumor progression in the melanocytic system: common acquired nevi and atypical dysplastic nevi.
Semin Diagn Pathol. Natural history of dysplastic nevi. Meta-analysis of risk factors for cutaneous melanoma: I. Common and atypical naevi. Eur J Cancer. Atypical moles and cancerous moles often have an asymmetrical shape with two, non-identical halves. Common moles, on the other hand, have smooth, even borders with distinct edges. If an atypical mole starts to grow and develops areas of red or blue pigment, this is indicative of melanoma.
E Evolving : Any changes in the appearance of a mole should be noted and brought to a dermatologist immediately. If any new symptoms like bleeding, crusting, or itching develop, this can also indicate skin cancer. Although atypical moles are not cancerous, atypical moles have a similar appearance to cancerous moles. Performing self-examinations regularly, using the ABCDE warning signs as a guideline, is critical for detecting skin cancer before it develops further.
Every month, examine your skin in the mirror and pay close attention to your moles. Assess the border, color, size, and shape of every mole and stay conscious of any changes or evolution over time. If your dermatologist identifies a suspicious atypical mole on your body, there are a few treatment options available to remove the mole, examine the skin cells and treat skin cancer if necessary. The first step to treat melanoma is to remove the mole or an area of the mole and examine the skin cells.
During a shave biopsy procedure, a thin layer of skin in the affected area is removed with a small blade similar to a razor. A local anesthetic is typically applied to numb the area before removing the skin. Stitches are not necessary to repair the skin after a shave biopsy. A scab will form over the wound, which generally heals the skin within a week or so. Punch biopsies remove a larger area of skin than shave biopsies.
During these biopsies, a rounded blade is rotated around the area to remove a thick skin sample that includes multiple layers of the skin, including the epidermis, dermis, and subcutis. Because a punch biopsy extracts multiple layers of skin, stitches are sometimes required to close the wound. A bandage will be placed over the area after the mole removal procedure to prevent further bleeding. A surgical excision biopsy procedure involves the removal of an entire piece of skin tissue on and around the mole, by use of a scalpel.
Surgical excision biopsies remove the entire skin lesion, down to the subcutis skin layer.
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