Table 2.

Most recent analysis of incidence of melanoma in children (age 0–16 years) with congenital melanocytic naevus (CMN) by different phenotypic groupings

Phenotypic subdivisions of the same cohort	n/N (%) of cutaneous melanoma in childhood	n/N (%) of primary CNS melanoma in childhood	n/N (%) of melanoma with lymph node (n = 1) or missing data primary site (n = 2)	Total n/N (%) of melanoma in childhood
Single CMN of any size	0/82 (0)	0/82 (0)	0/82 (0)	0/82 (0)
Multiple CMN where the largest CMN is < 60 cm projected adult size	2/199 (1)	0/199 (0)	1/199 (< 1)	3/199 (1)
Multiple CMN where the largest CMN is > 60 cm projected adult size, or where there is no one clearly larger CMN	0/88 (0)	6/88 (7)	1/88 (1)	7/88 (8)
Multiple CMN of any size or number and a normal screening MRI of the CNS	1/179 (< 1)	1/179 (< 1)	1/179 (0)	3/179 (2)
Multiple CMN of any size or number, and the finding of any congenital neurological disease seen on screening MRI of the CNS	1/51 (2)	5/51 (10)	0/51 (4)	6/51 (12)

Data collected prospectively from our U.K. cohort, 1988–2016, where face‐to‐face phenotyping occurred and melanoma was not present at the time of referral (n = 448). Ten children developed melanoma in this prospective cohort, of whom nine had had a screening magnetic resonance imaging (MRI) of the central nervous system (CNS). Multiple CMN is defined as two or more at birth. Where numbers do not add up to 448 this is because of individual items of missing data in the older phenotyping data.