Nevus spilus is also known as speckled lentiginous nevus because it has a spotted appearance with a background light brown discoloration. These birthmarks are very common, occurring in 1-3% of the population. They are thought to be a form of congenital nevi because they usually appear at birth or soon thereafter. There are, however, some speckled lentiginous nevi which appear later in life.
Nevus spilus is characterized by a tan to light brown patch of skin with darker brown bumps and freckles within it, which can be present anywhere on the body. The darker brown areas can represent different types of moles (nevi), which are almost exclusively benign in nature. However, approximately 20 cases of malignant melanoma arising in a nevus spilus have been reported in the literature.
Because the development of melanoma in nevi spili is extremely rare, surgical excision is not mandatory and is probably unnecessary. Your doctor may choose to follow the lesion with serial photographs or by using tools such as dermoscopy which allows your doctor to detect changes in the lesion more precisely. If any concerning areas arise in a nevus spilus, those areas can be biopsied to rule out atypical nevi or melanoma arising in a nevus spilus.
Cohen LM. Nevus spilus: congenital or acquired [editorial]? Arch Dermatol 2001;137:215-216.
Johr RH, Schachner LS, Stoltz W. Management of nevus spilus. Pediatr Dermatol 1998;15:407–409.
Gregg Severs, D.O.
Department of Dermatology
Philadelphia College of Osteopathic Medicine/Frankford Hospital