Juvenile xanthogranulomas are highly prevalent but transient in young children with neurofibromatosis type 1

Journal of the American Academy of Dermatology

Volume 71, Issue 2, Pages 389–390, August 2014 

 

Although juvenile xanthogranulomas (JXGs) are known benign cutaneous tumors that are sometimes observed in children with neurofibromatosis type 1 (NF-1), their real prevalence and natural history is still a matter of debate. A recent study reported a prevalence of 8.5% in 59 NF-1 children.¹ We examined the natural history of JXG in a retrospective cohort study of young children with NF-1. A clinical multidisciplinary follow-up was performed as recommended in our NF clinic.² In this study, every child with NF-1 diagnosed before age 7 years, according to National Institutes of Health criteria, between 2000 and 2010 were included. Mean follow-up was 59.6 ± 29.3 months. Among 40 children, 37.5% (15/40) had at least one JXG lesion. JXG lesions were often multiple (2.9 ± 2.5 lesions per child). The mean age at JXG diagnosis was 23.53 ± 17 months. The mean age at NF-1 diagnosis was 29.06 ± 16.3 months (range, 11.8-74 months) in the group with JXG and 40.02 ± 21.3 months (range, 6.5-73 months) in the group without JXG (P = .054). These results are similar to the findings of a recent retrospective study conducted by Ferrari et al.³ In this study, the authors revealed a high and unusual frequency (30%) of JXG in 20 NF1 children younger than 2 years. In contrast, JXGs were not observed in children older than 9 years or in adults. In our study, we observed spontaneous regression of JXG in 90% (9/10) of patients with a mean age of 46.5 ± 17.7 months (these data were missing for 5 children). Four of 15 children (26.6%) with JXG had isolated café au lait macules (CALMs) but lacked other signs of NF-1 when JXG was identified. For these patients, an NF-1 diagnosis would have been made 13 months earlier if JXG had been considered as a diagnostic criterion. We did not observe any significant differences in the prevalence of NF1 complications, including risk for leukemia, in children with or without JXG. Especially, we observed 1 case of myeloproliferative syndrome in each group (1 case of acute myeloid leukemia in the group without JXG and 1 case of juvenile myelomonocytic leukemia in the group with JXG).

In conclusion, our results suggest that multiple JXG lesions are highly prevalent in children younger than 2 years with NF1. However, these are transient and spontaneously disappear before a child reaches 5 years in most cases. Therefore, prevalence of JXG is low in children and adults in whom details regarding age at examination have not been recorded.¹ Clinically, JXG can be difficult to notice and is therefore underdiagnosed by nondermatologists. It is unclear whether JXG constitutes a risk factor for leukemia in children with NF1 as has been previously reported. Because CALMs are frequently the only diagnostic criteria in young children with NF-1 over several years, especially in sporadic cases, there is a need to identify other early clinical diagnostic criteria. JXG might be a good candidate diagnostic criterion; however, further investigation is required.