Peltonen S, et al. - Researchers investigated the incidence, risk and prognosis of malignancies in neurofibromatosis type 1 (NF1) patients <20 years of age in the Finnish NF1 cohort. A total of 524 persons born in 1987–2011 and followed through the files of the Finnish Cancer Registry from birth up to age 20 years were included, with 8,376 person years. A standardized incidence ratio (SIR) of 35.6 was estimated as 53 patients had cancer <20 years of age. The central nervous system (CNS) was identified to be the most frequent location of pediatric cancers; there were 45 cases and the SIR was 115.7. A cumulative risk of 2.7% by age 20 was noted for nine malignant peripheral nerve sheath tumors (MPNSTs). They did not find any case of leukemia. A considerable excess mortality was observed in NF1 patients, with a standardized mortality ratio (SMR) of 73.1. Overall, in patients with NF1, the malignancies of major concern were brain tumors in childhood and MPNSTs in adolescence. Compared with the literature, the reported risk for myeloid malignancies in this study may not be as high.