Sclerosing Bone Dysplasias: Review and Differentiation from Other Causes of Osteosclerosis

Abstract

Sclerosing bone dysplasias are skeletal abnormalities of varying severity with a wide range of radiologic, clinical, and genetic features. Hereditary sclerosing bone dysplasias result from some disturbance in the pathways involved in osteoblast or osteoclast regulation, leading to abnormal accumulation of bone. Several genes have been discovered that, when disrupted, result in specific types of hereditary sclerosing bone dysplasia (osteopetrosis, pyknodysostosis, osteopoikilosis, osteopathia striata, progressive diaphyseal dysplasia, hereditary multiple diaphyseal sclerosis, hyperostosis corticalis generalisata), many of which exhibit similar pathologic mechanisms involving endochondral or intramembranous ossification and some of which share similar underlying genetic defects. Nonhereditary dysplasias include intramedullary osteosclerosis, melorheostosis, and overlap syndromes, whereas acquired syndromes with increased bone density, which may simulate sclerosing bone dysplasias, include osteoblastic metastases, Paget disease of bone, Erdheim-Chester disease, myelofibrosis, and sickle cell disease. Knowledge of the radiologic appearances, distribution, and associated clinical findings of hereditary and nonhereditary sclerosing bone dysplasias and acquired syndromes with increased bone density is crucial for accurate diagnosis.

Imaging aspects of Camurati-Engelmann disease

“…2,3 Intramembranous ossification occurs in the cortex of tubular bones (such as femurs) and the flat bones of the skullcap, the upper facial bones, tympanic temporal bones, vomer and medial pterygoid plate. 4 The hereditary disorders related to this type of ossification are: generalized cortical hyperostosis (van Buchem's disease and variants), hereditary multiple diaphyseal sclerosis (Ribbing disease) and progressive diaphyseal dysplasia (Camurati-Engelmann's disease). 4 Although ErdheimChester disease is considered part of an acquired (and not inherited) syndrome that simulates sclerosing bone dysplasia, 4 it is also part of the differential diagnosis.…”

“…4 The hereditary disorders related to this type of ossification are: generalized cortical hyperostosis (van Buchem's disease and variants), hereditary multiple diaphyseal sclerosis (Ribbing disease) and progressive diaphyseal dysplasia (Camurati-Engelmann's disease). 4 Although ErdheimChester disease is considered part of an acquired (and not inherited) syndrome that simulates sclerosing bone dysplasia, 4 it is also part of the differential diagnosis. 3 Eventually, the possibility of osteopetrosis could be suggested; however, this disorder derives from an endochondral ossification defect (which gives rise to bone marrow) 4 and is therefore an ossification condition of the medullary and not the cortical region.…”

“…4 Although ErdheimChester disease is considered part of an acquired (and not inherited) syndrome that simulates sclerosing bone dysplasia, 4 it is also part of the differential diagnosis. 3 Eventually, the possibility of osteopetrosis could be suggested; however, this disorder derives from an endochondral ossification defect (which gives rise to bone marrow) 4 and is therefore an ossification condition of the medullary and not the cortical region.…”

“…In generalized cortical hyperostosis (van Buchem's disease and variants), 4 facial abnormalities occur, such as flattened forehead, elongated jaw and syndactyly of the second and third fingers. Meanwhile, in hereditary multiple diaphyseal sclerosis (Ribbing disease) 4 there is unilateral or bilateral asymmetric/asynchronous involvement of the long bones, typically the tibia and femur, 4 as well as non-involvement of skullcap. 4 Since the patient in this study has atypical fascicles, bilateral and symmetrical bone involvement and cortical thickening in the skull radiography, other diagnostic possibilities would be more likely.…”

“…Meanwhile, in hereditary multiple diaphyseal sclerosis (Ribbing disease) 4 there is unilateral or bilateral asymmetric/asynchronous involvement of the long bones, typically the tibia and femur, 4 as well as non-involvement of skullcap. 4 Since the patient in this study has atypical fascicles, bilateral and symmetrical bone involvement and cortical thickening in the skull radiography, other diagnostic possibilities would be more likely. These characteristics 4 are seen both in Erdheim-Chester disease (non-Langerhans cell histiocytosis), and in progressive diaphyseal dysplasia (Camurati-Engelmann disease).…”