QIs hair in a congenital mole actually a good sign?

Typically, hair growth within a mole is a feature of congenital nevi although collision of a new mole and pre-existing hair follicle is possible. The largest concern with a congenital nevus is the potential for developing into a melanoma. Hair growth, which can become more prominent with hormonal influence during puberty, indicates tissue within the nevus is healthy enough to support normal hair growth. Loss of hair growth within a congenital nevus could be a concerning feature in certain clinical scenarios. For congenital nevi, the largest risk factor for development into melanoma is size. Transformation arising within small (<1.5cm) or intermediate (1.5-10cm) congenital nevi is seen in <1% of cases and occurs predominantly in adulthood. However, data suggest melanoma develops in 2-5% of patients with a large (>20 cm2) congenital nevi, prominently in their first decade of life.1 These patients should be referred to an experienced dermatologist and a pediatric surgeon at birth for close follow-up and discussion of the risks and benefits of surgical intervention.2

References:

1. Kugar et al. J Craniofac Surg. 2021
2. Shah KN. Semin Cutan Med Surg. 2010