Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis caused by the expression of CD68-positive and CD1a-negative foam tissue cells. which is polar in pediatric patients. The study reports a case of an 8-year-old Chinese boy who presented with polydipsia and polyuria for 4 years. followed by central nervous system symptoms. https://www.hindigyanvishv.com/limited-stock-No-Face-No-Case-Logo-T-Shirt-special-save/