Subungual melanoma

ABCDEFs of detecting subungual melanoma: The most salient features of subungual melanoma (Figure 5) can be summarized with the following:

A= Age (peak incidence is in the fifth to seventh decades of life), and African Americans, Asians, and Native Americans are most affected
B= Brown-to-black pigmented nail band with blurred borders and breadth >3 mm
C= Change in size of the nail band (recent, rapid, and sudden)
D= Digit most commonly involved on hands or feet (first, followed by the hallux and second digit). Dominant hand more often involved, single digits more commonly than multiple digits
E= Extension of pigment into proximal or lateral nail plate (Hutchinson’s sign)
F= Family or personal history of dyplastic nevus syndrome or previous melanoma. 

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Clinical presentation: A pigmented lesion that arises subungually or periungually and/or a dystrophic nail plate that develops, especially after a traumatic incident, should raise suspicion of subungual melanoma.  

Background: Subungual melanomas represent 0.7%-3.5% of all melanomas. Five-year survival rates range from 16% to 87%, depending on extension/depth of the tumor. Amelanotic lesions account for 25% of cases.

Differential diagnosis: Pyogenic granuloma shares some of the same characteristics as subungual melanoma. Both are dark-appearing growths. However, pyogenic granulomas are more papular; well-defined; fluctuant; sometimes tender; and a deeper, violaceous color similar to thrombosed blood.

Treatment: Biopsy is required to determine the extent of disease. When involvement is localized, surgical removal with clear margins is sufficient. More widespread involvement can be treated with amputation of the affected digit with or without systemic chemotherapy and use of interferon.

Ms. Jacobson practices dermatology in Lancaster, Pa., and operates the Web site Ms. Zajac practices medical and cosmetic dermatology in Bethesda and Germantown, Md., and serves on the board of directors for the Society of Dermatology Physician Assistants.