< Current issue
Dermatopathology: Practical & Conceptual July - September 2001
Evolution in Thinking: Criteria for Clinical Diagnosis of Melanoma, 1947–2000: A Critique in Historical Perspective
Mary Aldrene L. Tan, M.D.
A. Bernard Ackerman, M.D.
Becker and Obermayer
Ormsby and Montgomery
Sulzberger and Wolf
Pillsbury, Shelley, and Kligman
Fitzpatrick and Clark
Lewis and Wheeler
Callen, Stawiski, and Voorhees
Roses, Harris, and Ackerman
Dobson and Abele
Friedman, Rigel, and Kopf
Fitzpatrick, Rhodes, Sober, and Mihm
Koh and Rogers
McCarthy et al.
Mooi WJ and Krausy
Fitzpatrick, Milton, Balch, Shaw, McCarthy, and Sober
National Institutes of Health Consensus Conference
Holzle, Kind, Plewig, and Burgdorf
Marghoob, Slade, Kopf, Rigel, and Friedman
Arndt, Wintroub, Robinson, and LeBoit
Elder and Elenitsas
Maize et al.
Langley, Fitzpatrick, and Sober
Farmer and Hood
Fleischer, Feldman, Katz, and Clayton
Ackerman, Kerl, Sánchez, et al.
Arndt, Wintroub, Robinson, and LeBoit
"The typical textbook melanoma is characterized by the mnemonic
olor variegation, and
iameter. Unlike moles, melanoma is usually asymmetric (i.e. it cannot be evenly bisected). The border of the lesion is irregular, but the edge usually remains distinct, at least in part. Melanomas display an admixture of colors, including black, blue, and even pink. An area of pigment loss in some part of the lesion (regression) is an important distinguishing feature for some early melanomas. Once fully developed, benign melanocytic nevi seldom change in diameter. If a lesion doubles in size over a period of a few months, malignant degeneration should be considered. Although melanoma can be identified at any size, lesions measuring larger than 6 mm in diameter should be assessed carefully for other atypical clinical features in order to rule out a malignant process.
Change in size also includes a change in surface elevation: a part of the tumor will become raised from the skin. It is important to make the diagnosis of melanoma before this event, as the development of a nodular component is a sign of an advanced lesion. These nodules are usually black or blue-black but are sometimes red (amelanotic).
The development of an intermittent, nonsevere itch is a useful sign in the diagnosis of melanoma. Tenderness or pain is a late sign and is of no help in making the diagnosis in the majority of patients."
Arndt KA, Wintroub BU, Robinson JK, LeBoit PE.
Primary Care Dermatology.
Philadelphia: W.B. Saunders Company, 1997: 1545.
Much of what is stated by Arndt and his colleagues has been said many times since the oversimplified ABCDs were first introduced in 1985. They are not correct to assert that "If a lesion doubles in size over a period of a few months, malignant degeneration should be considered." In fact, Spitz's nevi, especially in children, often more than double in size in the weeks following the appearance of them, but melanomas, except for those that are nodular and tumorous, tend to grow very slowly. Slow growth is one of the main characteristics of macules of melanoma, and that is why it is so important for clinicians and histopathologists to be able to make the diagnosis of melanoma at the macular (
) stage when simple excision is curative. The notion that "lesions measuring larger than 6 mm in diameter should be assessed carefully . . . to rule out a malignant process" is misleading; when Clark, in 1978, introduced the notion of the B-K mole, he thought that large size was the sine qua non for identification of those lesions. In fact, before coming to designate the lesion "dysplastic nevus," he and his coworkers called that exceedingly common proliferation of melanocytes the "large atypical mole." So-called dysplastic nevi may be greater than 6 mm in greatest diameter (althought the overwhelming majority of them are much smaller than that), but so, too, are other types of acquired melanocytic nevi at times greater than 6 mm in diameter,
Spitz's nevus, and many congenital nevi are very much larger than that. In short, the number "6 mm" has no worth to a clinician or histopathologist in assessing a pigmented lesion for the purpose of coming to a specific diagnosis of nevus or melanoma.
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