NAIL APPARATUS MELANOMA (Subungual Melanoma)

The subungual melanoma emanates from the nail matrix. Thus, it often initially presents as longitudinal melanonychia (LM). At that point, the lesion may only represent melanoma in situ. Later, destruction of the nail occurs and the melanoma may spread to the surrounding skin. Amelanotic subungual melanoma may occur [Cutis 2000;65;303].

Clinical

Several clinical presentations occur including:

• Longitudinal melanonychia alone
• LM along with nail dystrophy
• Hyperpigmentation of the periungual skin
• Pigmented nail bed mass
• Non-pigmented (amelanotic) nail bed mass

For LM, initially, there is a longitudinal streak along the nail. Over time, it darkens and widens. At some point, the lesion may thicken, and the pigment extend onto the proximal nail fold or onto the distal fingertip.

Pigmented or amelanotic nodules may develop in the nail bed. The process, when advanced, may destroy the nail entirely.

Hutchinson's sign--the extension of pigment onto the nail fold--is characteristic of melanoma. It is not pathognomonic, however, as pseudo-Hutchinson’s sign--hyperpigmentation in the absence of melanoma--does occur.

Treatment

Any suspicious lesion should be biopsied. Surgical excision by a trained specialist is in order.

Additional Pictures

The above melanoma has spread to the fingertip.

RegionalDerm

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