Melanoma on dysplastic nevus spilus

Nevus spilus is found with relative frequency. It is observed as as tan to brown macule serving as base to a speckle of smaller and darker maculo-papular elements. On rare occasions it turns into a malignant melanoma.

To describe one case with some characteristics different from routine observations and to revise the cases published reporting nevus spilus that turned into malignant melanoma, in order to point out the most frequent aspects.

The 17 patients with nevus spilus and melanomas, including ours, were white, with ages between 35 and 56 years. Most of the cases were localized in the dorsal region. Five patients were men. Almost all nevus were congenital and their size ranged between 2 and 10 cm in diameter. Histologically, the speckled spots were junctional nevus, and few of them had dysplastic characteristics. Melanomas corresponded to the extensive superficial type MES; one of them was nodular. Some had systemic ganglial metastases and three of the patients are known to have died. Our patient had an intradermal cellular nevus on the man spot, and terminal hairs could be observed on it. The speckled elements were junctional nevus with dysplastic cells.

Nevus spilus must be closely monitored, because it may turn into a malignant melanoma.