|ECR 2019 / C-2905|
|Constitutional disorders of the bone : rare yet to know : a personal experience and a systematic overview|
Findings and procedure details
We retrospectively reviewed the imaging findings of patients diagnosed with congenital bone disorders.
15 patients were enrolled in our study. We counted 9 males and 6 females with an average age of 3.5 years old.
Plain radiography was the main imaging modality and was performed in all our patients.
Findings were as follow: osteoporosis in 4 cases, achondroplasia in 4 cases, Pyle’s disease in 2 cases, Leri-weil syndrome in 1 case, osteogenesis imperfecta in 1 case, metaphyseal chondrodysplasia schmid type in 1 case and clinodactyly associated to a Turner syndrome.
Chondrodysplasias are responsible for growth disorders and /or developmental abnormalities of the bone or cartilage. The diagnosis is often made during the early infancy and is suspected in the presence of intrauterine growth restriction or those who present with short stature, especially if there is growth disproportion.
There are lethal neonatal forms namely:
• Thanatophoric dysplasia
• Platyspondylic lethal skeletal dysplasia
• Gracile bone dysplasia
Signs that suggest these forms are:
-Femur length ratio / abdominal circumference < 0.16
-Chest circumference , growth Percentile < 5 (pulmonary hypoplasia)
-Chest circumference / abdominal circumference <0.8
The most frequent dysplasias of prenatal onset are osteogenesis imperfecta type II, thanatophoric dysplasia and achondrogenesis II.
Other most frequent forms of bone dysplasia that evolve through life can be grouped on the bases of the affected site:
• Group I: Epiphyseal dysplasias with or without spinal involvement: Chondrodysplasia punctata, Type II collagenopathies, such as congenital and tardive epondyloepiphyseal dysplasia, Kniest's dysplasia, type II achondrogenesis, spondyloepimetaphyseal dysplasias, multiple epiphyseal dysplasia, pseudoacondroplasia, mucopolysaccharidosis and diastrophic dysplasia.
• Group II: metaphyseal dysplasias: Rhizomelic as in achondroplasias; hypochondroplasia and thanatophoric dysplasia and metaphyseal chondrodysplasia; or mesomelic or acromelic shortening, such as chondroectodermal dysplasia.
• Group III: Dysplasias with altered bone density: Osteogenesis imperfecta and pycnodysostosis.
Osteogenesis imperfacta is a complex group with a clinical and molecular heterogeneity due to lack of type I collagen. Overall there are 4 types:
• Type I: moderate forms with blue sclera
• Type II: lethal forms
• Type III: severe forms (progressive deforming)
• Type IV: similar to type I without blue sclera
Osteogenesis imperfacta affects both bone quality and quantity. The hallmark radiological feature is osteoporosis and fragile bones that can fracture easily (Figure 1).
Achondroplasia is responsible of micromelic dwarfism with rhizomelic shortening (Figure 2-3-4).
It is suspected in the presence of:
- Frontal bulging, mesofacial hypoplasia, narrow magnum foramen
-Short ribs, spinal canal stenosis with decreased interpedicular distance
-In the pelvis the iliac bones have flat acetabular roof and narrow sacrocytic notch.
-Rhizomelic shortened extremities.
Metaphysal chondrodysplasia is characterized by a relatively short stature with shortened extremities and bowed legs
3 types: Schmid type: mild form, due to mutation in type X collagen.
Pena and Vaandrager type: intermediate type
Jansen type: severe form with irregular mineralization in the metaphyses
Metaphysal chondrodysplasia Schmid type: is characterized by a relatively short stature with shortened extremities and bowed legs (genu varum (Figure 4)).
Leri-Weill syndrome is an autosomal dominant dyschondrosteosis characterized by mesomelic shortening of limbs. Patients present with schortened forelegs and forearms. This type of altered development of the lower arm gas often been referred to a Madelung’s deformity.
Osteopetrosis (group 26), also called Albers-Schonberg disease, is due to defective osteoclastic activity. It has two varieties, infantile autosomal recessive and benign adult autosomal dominant variety. Infantile or ‘malignant’ osteopetrosis is a severe form that tends to present early (Figure 7).
Thematically related posters
ECR 2019 / C-0326
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