Other possible causes of arising CPP could be represented by increase of nerve growth factor (NGF) in the endometriotic lesion area, and this may worse the disease progression by two different way: on one hand it could emprove “neural sprouting” and so create new painful afferents to the CNS, and, on the other hand, it could be considered itself a mediator that may exacerbate the CPP [26]. Here, NGF is linked to central precocious puberty.