Malignant melanoma of the toenail apparatus

Subungual melanoma is an unpredictable and aggressive tumor with a propensity to metastasize widely. Because it is an uncommon condition, statistical analysis of its behavior patterns is difficult, factors that determine its prognosis are unclear, and optimal management is ill defined.

A detailed review was undertaken of the clinical and histologic features of subungual melanomas arising from the toenail apparatus in 25 patients treated at the Sydney Melanoma Unit during a 40-year period. Treatment and outcomes were analyzed.

Most of the lesions were situated on the great toe in elderly patients of Anglo-Celtic extraction. Antecedent trauma to the toe was frequently reported and delayed diagnosis was usual. There was great variation in Breslow thickness and Clark's level, but these indices were found to have less prognostic significance than for other forms of cutaneous melanoma.

The treatment of subungual melanoma of the toenail apparatus is primarily surgical, by amputation at or proximal to the metatarsophalangeal joint. Even if there is no clinical evidence of metastatic disease in regional lymph nodes, radical node dissection is desirable. The condition is most appropriately managed at a specialist center.