Levine

 
" . . . The ABCD rule has been promulgated as a pneumonic [sic] device to assist in detection:
 
1.Asymmetry of lesional contour is an important early sign of malignant change. Nevi are almost always uniform to the point of mirror symmetry. One should become concerned if a pigmented lesion becomes even minimally lopsided. An example of this would be a small papule appearing at the margin of a completely flat lesion.
2.Border irregularity in melanoma may manifest itself as a notching or feathering.
3.Color variation is often the most obvious early change in melanoma. The "flag sign" has been described, in which variations of red, white, and blue colors are randomly dispersed through an otherwise brown or black lesion.
4.Diameters of acquired benign nevi are usually less than 0.6 cm. Congenital nevi, dysplastic moles, and seborrheic keratoses may be considerable larger than this, however. Thus a pigmented mole which is 0.6 cm or greater in size should raise one's [sic] suspicions, but other differential diagnostic possibilities must be considered using this criterion alone."
 
Levine N. Pigmentation and Pigmentary Disorders. Boca Raton: CRC Press, Inc., 1993:262.
 

Brief critique

 
Levine concentrates on "early" signs and on changes in melanoma. Macular lesions, however, may not be markedly asymmetrical, show "feathering" (whatever that may be), be associated ever with "red, white, and blue colors," or present themselves as "0.6 cm or greater in size."Although Levine directs his attention to recognition of melanoma at an early stage, he, nonetheless, advises that "if a pigmented lesion becomes even minimally lopsided," such as "a small papule appearing at the margin of a completely flat lesion," a clinician should become concerned. By the time that a papule has developed, a melanoma no longer is very early in the sense that it is in situ, but "invasive," thereby putting a person who bears it at risk for metastasis.