Engelmann Disease, also known as progressive diaphyseal dysplasia, is a rare genetic condition that affects the bones and muscles. This disease is characterized by progressive thickening of the bones, particularly in the diaphysis (shaft) of long bones. The term "Engelmann Disease" is mostly used in medical and scientific literature. However, there are a few synonyms that can be used interchangeably to refer to this condition. These include progressive diaphyseal dysplasia, Engelmann's syndrome, Engelmann's disease, Engelmann-Camurati disease, and diaphyseal dysplasia. Although the name may differ slightly, the symptoms and presentation of this disease remain consistent across all synonyms.