Clinical presentation
Nail pigmentation is the first clinical sign of subungual melanoma in more than 75% of cases, but few patients present at this stage. Instead most patients delay presentation until changes in the nail contour are evident, secondary infection supervenes, or ulceration of the nail bed with granuloma formation manifests.1
Levit et al5 surveyed the world literature on “subungual melanoma” in 2000 and, based on their findings, described the ABCDEF mnemonic (TABLE 1) to describe the salient features. When considering a nail bed lesion, the presence of any one of these features should raise the clinician’s index of suspicion for subungual melanoma, while the presence of multiple features should raise a significantly higher concern.
TABLE 1
Salient features of subungual melanoma
| A=Age (5th to 7th decades), African-American, Asian, American Indian |
| B=Brown/Black pigment, Breadth (>3mm), Border variegation |
| C=Change in nail band or lack of change in nail morphology despite, presumably, adequate treatment |
| D=Digits most commonly involved (thumb, hallux) |
| E=Extension of pigment onto the proximal/lateral nail fold (Hutchinson’s sign) |
| F=Family or personal history of melanoma |