Juvenile xanthogranuloma (JXG) is the most common form of non-Langerhans histiocytosis (LCH). JXG falls under group “C” (cutaneous limited), and group “L” (extracutaneous, systemic) histiocytosis. It frequently occurs in infants and young children but can occur in patients at any age.  

Morphologically, JXGs are mainly composed of infiltrates of uniform, mononuclear histiocytes with a variable degree of intracytoplasmic lipidization (foamy histiocytes) and most often scattered multinucleated giant cells (Touton and non-Touton; although multinucleated cells were not present in the current case). In addition, a scattered inflammatory infiltrate (lymphocytes or eosinophils) is present in the background. Typically, and as was true in this case, immunostains are positive for factor XIIIa, CD163, CD68 but negative for CD1a and S-100.  

Although JXG is commonly limited to the skin, extracutaneous JXG also exists. There are a few case reports of JXG involving the nervous system (CNS and PNS). Brain is the most common site (53%), followed by the spinal cord (13%). The clinical and radiologic manifestation is nonspecific and in contrast to LCH, JXG of the CNS is indolent.