Juvenile Xanthogranuloma and Nevus Anemicus in the Diagnosis of Neurofibromatosis Type 1

Abstract

We found a high frequency of JXG and NA in patients with NF1, especially in children younger than 2 years with fewer than 2 diagnostic criteria. Hence, JXG and NA appear helpful in improving early diagnosis of NF1 in young children and infants.

Nevus Anemicus: A Distinctive Cutaneous Finding in Neurofibromatosis Type 1

“…The subtle clinical appearance of NA and absence of symptoms can make its detection difficult, so it must be looked for purposely. Because NA is present early in life and its prevalence is higher than that of other classic NIH criteria for NF1, we think, in agreement with other authors , that NA may constitute a clinical diagnostic criterion for NF1 and that detection of NA may be of help in clinically distinguishing NF1 from other genodermatoses with CALS and freckling. Dermatologists, pediatricians, and physicians involved in the care of patients with suspected NF1 must be aware of this clinical sign as part of the routine physical examination and take into account its predictive diagnostic value.…”

“…NA did not receive further attention in the literature until 2013, when we and three other groups assessed large series of individuals with NF1 and associated NA . Not surprisingly, retrospective studies yielded much lower estimates than prospective assessments , probably because NA is clinically subtle and may be easily overlooked unless purposely searched for (Fig. ).…”

“…Their estimated prevalence in individuals with NF1 ranges from 0.7% in adults to 3.9% to 18.2% in children . Although we did not have a long enough follow‐up to determine how many patients with NA or JXG later had definite NF1, one study found that in 8 of 10 patients with only one diagnostic criterion for NF1 at the first visit with NA or JXG the disease was later confirmed .…”

Neurofibromatosis Type 1 Diagnosed in a Child Based on Multiple Juvenile Xanthogranulomas and Juvenile Myelomonocytic Leukemia

“…The occurrence of the association between JXG, NF1, and JMML has been reported more than 20 times in the literature. Children with NF1 have a prevalence of JXG as high as 18% to 30% , depending on the age of the child, because JXGs tend to regress at the age when NF1 becomes clinically evident. The risk of developing JMML is 200 to 500 times greater than in children with NF1 .…”

“…JMML generally affects children before the age of 6 years, therefore clinical surveillance of children with JXG and NF1 should be focused on this age group. Based on these data, we would like to emphasize the high level of suspicion of NF1 stigmata in children with multiple JXGs, including examination with a Wood's light to look for café au lait spots and nevus anemicus as clinical clues to NF1 . With this knowledge, patients with JXG and NF1 who develop paleness, skin bleeding, infections, coughing, or unexplained fever should be biochemically tested.…”