Ischemic and infiltrative disorders of bone

Interruption of blood flow to the skeleton can cause ischemic necrosis (IN), a focal disorder that disrupts bone and cartilage. Legg-Calve-Perthes disease (LCPD), an archetypal form of IN, is a relatively common, complex, and controversial problem of IN of the capital femoral epiphysis in children. As for LCPD, symptoms result primarily from skeletal disintegration. The various clinical presentations of IN are sometimes divided into two major anatomical categories: diaphysometaphyseal and epiphysometaphyseal. Systemic mastocytosis (SM) comprises several disorders featuring increased numbers of mast cells. It is one of eight myeloproliferative neoplasms. Langerhans cell histiocytosis (LCH) is an extremely heterogeneous disorder that can include major congenital malformations. Many tissues and organs can be involved, including brain, lung, oropharynx, gastrointestinal tract, skin, and bone marrow. LCH tends to be benign and self-limiting when there is no systemic involvement.