1) Because of its poor prognosis, often related to delay in diagnosis, maintain a high index of suspicion for subungual melanoma in the proper setting and a sound understanding of which lesions need to be biopsied.
Subungual melanoma disproportionately affects nonwhites.
The cause of subungual melanoma is thought to be different from that of cutaneous melanoma, but it remains unclear.
Nail pigmentation is the first clinical sign of subungual melanoma in more than 75% of cases, but few patients present at this stage.
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.
The 2 most important signs of subungual melanoma are melanonychia striata (longitudinal brown to black pigmented streaks in the nail) and Hutchinson's sign, which is the spread of brown or black pigment from the nail bed, nail matrix, or nail plate onto the adjacent cuticle or onto the proximal or the lateral nail fold.
Nagi warned that subungual melanoma
is often asymptomatic and that up to 25% of cases can be amelanotic, so it is easily mistaken for pyogenic granuloma, chronic granulation tissue, or mycobacterial infection with nail dystrophy
Subungual melanomas seem to travel under the radar screen of many physicians, and are diagnosed relatively late in the course of disease partly because of their relatively low incidence and an appearance that can commonly be mistaken for other conditions, Carl Washington, M.
Most subungual melanomas originate in a pigmented nail streak, and this is important because it gives us the opportunity--as with other types of melanoma to make an early diagnosis and prescribe appropriate treatment," said Dr.
About 64%-74% of subungual melanomas are localized at the time of diagnosis.