“…These 'chor oid plexus XGs' are considered pseudoneoplastic [9,14], and can be distinguished from JXG by their histologic appearance, which consists chiefly of foamy histiocytes, cholesterol crystals, and eventually, giant cells and inflam matory infiltrates [9], Intracranial dural [34][35][36], spinal dural [37], and dif fuse leptomeningeal involvement [38] with XGs have been reported. Dural based forms generally occur in indi viduals with Langerhans cell histiocytosis, including Hand-Schuller-Christian (HSC) or Weber-Christian dis ease, and are generally distinguishable from JXG by his tological, immunohistochemical and electron microscop ic features [9,10,34,35,39], However, three recent reports of dural-based lesions more characteristic of JXG in children without HSC or Weber-Christian disease are unusual and noteworthy. Shimosawa et al [10] reported the case of an intradural, extramedullary JXG at T6-T9 in a 13-month-old causing progressive paraparesis, while Kitchen et al [11] reported a JXG arising from the SI nerve root sheath and invading the dorsal root of SI in a 15-year-old girl.…”