Juvenile xanthogranulomas of the nervous system: A report of two cases and review of the literature.

Juvenile xanthogranulomas (JXG) are uncommon non-Langerhans cell histiocytic proliferations which arise most often in children. While most cases present as solitary cutaneous lesions, occasional cases involve extracutaneous sites. Rare examples of JXGs have been reported involving all levels of the neuroaxis. We present two cases of JXGs involving the nervous system, and review the literature. The first patient was a 14-year-old female with headaches and a mass involving the left trigeminal nerve; pathologic examination showed a JXG. At 11 months follow-up, after administration of systemic chemotherapy, the patient remained stable with residual tumor. The second patient was a 15-year-old female with leg weakness and numbness, who underwent complete surgical resection of a dural JXG. At eight months follow-up, she showed no evidence of tumor, and was able to walk without difficulty. Review of the literature revealed 38 previously published reports of JXGs involving the nervous system. The CNS was involved in the majority (75%) of cases. The clinical characteristics of JXGs arising in the CNS varied significantly from cases in the peripheral nervous system (PNS); CNS tumors occurred in younger patients, more often males, and were more likely to be associated with concurrent cutaneous and extra-nervous systemic lesions. The clinical outcomes were similar for CNS and PNS lesions, with the caveat that all three lethal JXGs occurred in the CNS. The clinical and radiologic presentation of JXGs is nonspecific, thus necessitating biopsy and pathologic examination to arrive at the diagnosis. The pathologic differential diagnosis includes a heterogeneous group of histiocytic proliferations; immunostaining for histiocytic markers CD68, factor XIIIa, and Fascin, and the absence of Birbeck granules and CD1a immunoexpression suggests the diagnosis of JXG. In many cases, total surgical resection is curative. However, some cases will require additional chemotherapy and/or radiotherapy.