Poorly visible at birth congenital melanocytic nevus.

Abstract

The second observation 4 years later explains the apparent inconsistency of the two separated nevus lesions at birth; especially it demonstrates how a junctional melanocytic nevus can be poorly or no visible at birth. The history told us that the actual extent of the nevus was evident at the first exposure to the sun and that from that moment there was no further extension. Therefore, it is not conceivable that the nevus was absent at birth and increased so much in a few months. More realistic is the assumption that a junctional melanocytic nevus was already present at birth, but invisible because it had not yet started to produce melanin, that occurred after the first exposure (2).
A second consideration is that strangely hypertrichosis was already present at birth, though it got more evident with time (1). A final consideration should be made regarding the disappearance of the 2 mm dermal nevus, confirming the significant changes that congenital melanocytic nevus can undergo.