Eosinophilic granuloma - proximal femur


This patient has known (pathologically confirmed) Langerhans cell histiocytosis involving the skull and left femur. He went on to have prophylactic intra-medullary nail placement to prevent a fracture. The location of this lesion, within the cortex, is somewhat atypical with most such lesions located within the medullary cavity - appearance is however variable.