Skeletal dysplasias: A radiographic approach and review of common non-lethal skeletal dysplasias

Abstract

Skeletal dysplasias are not uncommon entities and a radiologist is likely to encounter a suspected case of dysplasia in his practice. The correct and early diagnosis of dysplasia is important for management of complications and for future genetic counselling. While there is an exhaustive classification system on dysplasias, it is important to be familiar with the radiological features of common dysplasias. In this article, we enumerate a radiographic approach to skeletal dysplasias, describe the essential as well as differentiating features of common non-lethal skeletal dysplasias and conclude by presenting working algorithms to either definitively diagnose a particular dysplasia or suggest the most likely differential diagnoses to the referring clinician and thus direct further workup of the patient.

Keywords: Achondroplasia; Algorithm; Approach; Multiple epiphyseal dysplasia; Radiograph; Review; Rhizomelia; Short limb dwarfism; Skeletal dysplasia; Skeletal survey; Spondylopepiphyseal dysplasia.

Figure 1

Spondyloepiphyseal dysplasia congenita. Lateral radiographs of dorsolumbar spine show platyspondyly (arrow, A) with severely reduced intervertebral disc spaces (arrow, B). Radiograph of pelvis (C) shows small femoral epiphyses (white arrow), horizontal acetabuli (black arrow) and short iliac wings (a). Radiograph of skull (D) shows relatively enlarged calvarium (arrow). Radiographs of lower limbs (E, F) show relatively short femurs and small epiphyses with secondary metaphyseal irregularity (arrow, F).

Figure 2

Spondyloepiphyseal dysplasia tarda. Lateral radiograph of lumbar spine (A) shows characteristic posterior hump (arrow). Radiograph of pelvis (B) shows bilateral flattened femoral heads, short necks and premature degenerative changes (arrow).

Figure 3

Multiple epiphyseal dysplasia. Radiographs of pelvis, knee and elbow (A-E) show epiphyseal irregularity in proximal femurs (arrow, A), around knee joints (arrow, B), elbow (arrow, C) with involvement of epiphyses of hands and feet (arrows in D, E) suggestive of multiple epiphyseal dysplasia. Radiograph of ankle (F) shows lateral tibio-talar slant. Radiograph of bilateral knees skyline view (G) and lateral view of left knee (H) show double-layered patellae (arrows).

Figure 4

Pseudochondroplasia. Lateral radiograph of spine shows typical central anterior tongue (arrow, A) in lumbar vertebrae. Radiograph of both hands (B) also show multiple abnormalities of epiphyses of metacarpals and phalanges with secondary metaphyseal widening (arrow).

Figure 5

Chondrodysplasia punctata. Oblique view radiograph of dorsal spine (A) shows coronal clefting (arrow). Radiographs of another patient with chondrodysplasia punctata show stippling of vertebral bodies (arrows B, C), in toes (D), tarsal bones (E) and in carpals (F).

Figure 6

Hurler’s syndrome. Radiographs of patient with Hurler’s syndrome show macrocephaly with enlarged J-shaped sella (arrow, A), cardiomegaly (arrow, B) and paddle-shaped ribs (arrow, E). Also note relative diaphyseal widening in humerus (upper arrow, C) and sloping lower ends or radius and ulna (lower arrow, C). Radiograph of hands (D) shows proximal pointing (arrow), osteopenia and flexion deformities in distal interphalangeal joints, Radiograph of spine (F) shows hypoplastic L1 and antero-inferior beaking (arrows).

Figure 7

Morquio’s syndrome. Radiographs of spine (A, B) show platyspondyly with maintained intervertebral disc height (arrow, A) and central beaking (arrow, B). Radiograph of hand (C) shows proximal pointing of metacarpals. Radiograph of pelvis and lower limbs (D) show delayed ossification of femoral heads, irregular epiphyses and secondary metaphyseal widening in proximal femur and around knee joint (arrows).

Figure 8

Achondroplasia. Radiograph of lower limbs (A, B) shows bilateral rhizomelic shortening with metaphyseal flaring (arrow, A) and chevron deformity in femur (arrow, B). Note trident hand appearance in (C). Radiograph of pelvis (D) shows short and broad pelvis (*), horizontal acetabuli (arrow) and round iliac wings. Radiographs of spine (E, F) show narrow interpedicular distance in lumbar spine (arrow, E) and posterior scalloping and thick, short pedicles (arrow, F). Radiograph of skull (G) shows enlarged cranial vault with narrowed foramen magnum (arrow).

Figure 9

Chondroectodermal Dysplasia (Ellis Van-Creveld Syndrome). Multiple radiographs of patient with chondroectodermal dysplasia show mesomelia (arrow, A), polydactyly on ulnar aspect with fused metacarpals (arrow, B), cardiomegaly with right side enlargement due to atrial septal defect (arrow, C) and acetabular hook (arrow, D). Also note flared iliac wings in pelvis.

Figure 10

Osteogenesis Imperfecta. Infantogram of 1-mo baby shows diffuse osteopenia with multiple fractures in extremities (arrow). Radiograph of another patient shows fractures in bilateral femurs with callus formation (arrow). Radiograph of spine (C) shows osteopenia with codfish vertebrae.

Figure 11

Osteopetrosis. Radiograph of skull shows diffusely increased density (A). Radiograph of bilateral femurs show obliteration of medullary cavity and Erlenmeyer flask deformity (arrow, B). Also note sandwich vertebrae (arrow, C) bone-within-bone appearance in pelvis (arrow, D) and increased density in hand bones (E).

Figure 12

Pyknodysostosis. Radiographs of skull (A, C) show hypoplastic mandible, open sutures and increased bone density (arrows, A). Increased bone desnity also noted in pelvis (B) and hands (D). Also note acroosteolysis (arrow, D).

Figure 13

Osteopoikilosis (A,B) and Melorheostosis (C). Radiographs of pelvis (A) and hand (B) of a patient with osteopoikilosis show multiple bilateral symmetrical sclerotic lesions in periarticular location (arrows, A and B). Similar changes were also noted in knees, elbows and vertebral bodies (not shown). Radiograph of lower limb (C) of a young patient with melorheostosis shows “flowing wax appearance“ (arrow, C).

Figure 14

Progressive diaphyseal dysplasia. Radiograph of patient with progressive diaphyseal dysplasia shows symmetrical thickening along bilateral femoral diaphysis (arrows) with sparing of epi- and metaphyses. The pelvis also shows increased bone density.

Figure 15

Cleidocranial dysplasia. Radiographs of skull (A, B) show open fontanelles and wormian bones (arrows, A) and hot cross bone appearance (arrow, B). Radiograph of chest(C) shows hypoplastic right clavicle (arrow). Radiograph of hand (D) shows elongated second digit with an accessory epiphyseal centre (arrow) Radiograph of pelvis (E) shows “chef-hat” shaped femoral heads (arrow) and widened pubis symphysis.

Figure 16

An algorithmic approach to skeletal dysplasias with spine and limb involvement. SEDT: Spondyloepiphyseal dysplasia tarda; CDP: Chondrodysplasia punctata; PSACH: Pseudoachondroplasia; EDM: Multiple epiphyseal dysplasia; CED: Chondroectodermal dysplasia.

Figure 17

An algorithmic approach to skeletal dysplasias with skull involvement.