Langerhans cell histiocytosis of the rib

Abstract Langerhans cell histiocytosis (LCH) is a rare systemic disease characterized by the proliferation and accumulation of Langerhans cells derived from bone marrow myeloid progenitor cells. The disease can affect a single organ or multi-organ system. The main sites involved in LCH include bones, lungs, central nervous system, liver, thymus, skin, and lymph nodes, causing focal or systemic effects. We report a rare case of LCH showing a single osteolytic lesion on the posterolateral side of the tenth rib of a 2-year-old boy who presented with upper back pain.