Accurate staging of nodal involvement in pediatric sarcoma patients is important to determine correct systemic and local therapy, with the goal to reduce subsequent recurrences. However, differences in lymph node staging strategies, definitions, and treatment protocols between the Children’s Oncology Group (COG), European Pediatric Soft Tissue Sarcoma Study Group (EpSSG), and the Cooperative Weichteil Sarkom Studiengruppe (CWS), complicate comparisons. In this article we try to establish internationally recognized recommendations for lymph node assessment and treatment of children and adolescents diagnosed with RMS and NRSTS according to the Consensus Conference Standard Operating Procedure methodology.

Juvenile xanthogranuloma (JXG) is a clonal non-Langerhans cell histiocytic disorder characterized by a variety of cutaneous and non-cutaneous manifestations, predominantly in children. The mitogen-activated protein kinase pathway (MAPK) is a key driver in many histiocytic disorders, including JXG. We report a rare presentation of JXG in the mastoid bone of a which recurred after surgery and was refractory to two lines of chemotherapy before responding to the MEK inhibitor trametinib, even in the absence of an identifiable MAPK pathway mutation. MEK inhibitors may be a therapeutic option for this sometimes difficult to treat disease.