BRAF V600E mutation in pediatric intracranial and cranial juvenile xanthogranuloma.

Juvenile xanthogranuloma (JXG) is a cutaneous form of non-Langerhans cell histiocytosis, primarily affecting children. The lesion is presumed to originate from either macrophages or dermal dendritic cells. JXG can rarely present as an isolated intracranial lesion and, in contrast to the dismal outcome of patients with systemic disease, cranial JXG has been shown to carry a more favorable prognosis. Here, we report for the first time 3 pediatric cases of JXG with a BRAF V600E mutation, 2 with intracranial lesions and 1 with cranial lesions. Although these intracranial/cranial lesions have been referred to as JXG, they likely differ from cutaneous JXG in both the clinical features and BRAF status. It may be more appropriate to classify intracranial/cranial JXG in the same group as Langerhans cell histiocytosis and Erdheim-Chester disease, which also have a BRAF V600E mutation. Further study of BRAF status in a larger series of JXG is warranted.

Usefulness of enzyme-1 and immunohistochemistry in the diagnosis of juvenile xanthogranuloma.

Skin biopsies from two children with juvenile xanthogranuloma were studied. Enzyme- and immunohistochemistry was used to establish the mononuclear phagocytic nature of the proliferating dermal elements. The usefulness of both techniques in the diagnosis and the differential diagnosis of this disease is suggested.