- Nevus comes from Latin and translated to: patch present at birth
- The Greek word of origin: σπιλος = spilos = dirt
- Translated together it means: dirty nevus
- It is often understood that nevus spilus is a melanocytic nevus within another melanocytics nevus , or better melanocytic nevi inside another one.
- Nevus spilus is actually a café-au-lait macule on which are located disseminated melanocytics nevi.
The café-au-lait is present at birth (congenital) whereas pigmented melanocytics nevi develop during childhood
- The confusion with a café-au-lait macule (which can occur in neurofibromatosis) is only possible in early childhood before the pigmented melanocytic nevi appear.
- Becker’s nevus is another possibility (it is not a melanocytic nevus but an organoid hamartoma)
- Note: melanoma development within a nevus spilus has been reported but remains rare. More commonly a Spitz nevus can be found within a nevus spilus.
Source of information: Harms M. Dermatologica Helvetica (The Swiss Journal of Dermatology and Venereology)