Age / Sex : 4 / M

Age / Sex :

M / 4Y

Chief complaint :

Delayed development

Achondroplasia

Discussion

Findings:

•      Limb

–      Shortening of proximal tubular bone
& metaphyseal flaring

Differential Diagnosis:

 osteochondrodysplasia, Ellis-van Creveld syndrome,
metatropic dysplasia, diastrophic dysplasia, thoracic dystrophy of Jeune,
pseudoachondroplasia, various spondyloepiphyseal and spondylo-metaphyseal
dysplasia

Diagnosis:
 

Achondroplasia

Discussion:

•     
AD/ sporadic (80%)

•     
Quantitatively defective endochondral bone formation

•     
Associated with advanced paternal age

•     
Epiphyseal maturation & ossification is not affected

•     
Normal intelligence and motor function

•     
Rhizomelic micromelia (short limbs, esp. proximal)

•     
Large head with prominent forehead and depressed nasal bridge

•     
T-L kyphosis in infancy

•     
Exaggerated lumbar lordosis with prominent buttock

Imaging findings

•     
Skull

–     
Brachycephaly with enlarged bulging forehead

–     
Shortened skull base

–     
Small foramen magnum

•     
Spine

–     
Interpedicular distance of lower L-spine remain the same at all levels or
decrese in the lower lumbar region

–     
Short pedicle on lateral view

–     
Vertebral body; posterior concavity, low height, anterior wedging; spinal
stenosis

–     
Pelvis

–     
Squared iliac bone (champagne glass)

–     
Flattened iliac bone (small sacro-sciatic notch)

•     
Extremities

–     
Shortening of proximal tubular bone & metaphyseal flaring

–     
Trident finger, brachydactyly

–     
High position of fibular head

–     
V-shaped configuration of distal femoral growth plate (medial slanting of
metaphysis)

References:

•      Bone and Joint Imaging

–      Resnick 3^rd Edition;
p1298-1300