Subungual Melanoma

Excerpt

Three distinct types of longitudinal melanonychia exist, including 1. lentigo, 2. nail matrix nevus, and 3. subungual melanoma. The first two conditions are benign lesions, while subungual melanoma is malignant. Subungual melanoma is a distinct subtype of cutaneous malignant melanoma arising from structures within the nail apparatus. It is ordinarily a variant of acral lentiginous melanoma, a malignant melanoma originating on palms and soles. Boyer originally recognized it in 1834. Hutchinson described the features in greater detail in 1886, offering a more accurate view of the condition. He described a specific sign strongly associated with subungual melanoma where the pigment extends beyond the nail and into the adjacent skin ("Hutchinson sign"). This article provides an up-to-date and accurate review of subungual melanoma and its management.

Nail unit melanoma, also called subungual melanoma, accounts for up to 3 percent of all melanomas in populations with lightly pigmented skin. However, it accounts for up to 30 percent of melanomas in populations with darkly pigmented skin.[14] In approximately sixty-five percent of cases, nail melanoma presents as a dark black, vertical band involving a single nail.[15] The band is usually wider than 3 mm, with proximal widening and irregular side borders. Nail plate dystrophy is a common finding.