World Journal of W J R Radiology Submit a Manuscript: http://www.wjgnet.com/esps/ World J Radiol 2014 October 28; 6(10): 808-825 Help Desk: http://www.wjgnet.com/esps/helpdesk.aspx ISSN 1949-8470 (online) DOI: 10.4329/wjr.v6.i10.808 © 2014 Baishideng Publishing Group Inc. All rights reserved. REVIEW Skeletal dysplasias: A radiographic approach and review of common non-lethal skeletal dysplasias Ananya Panda, Shivanand Gamanagatti, Manisha Jana, Arun Kumar Gupta Ananya Panda, Shivanand Gamanagatti, Manisha Jana, lopepiphyseal dysplasia; Multiple epiphyseal dysplasia; Arun Kumar Gupta, Department of Radiodiagnosis, All India Achondroplasia; Algorithm; Approach Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India Core tip: This article describes the radiographic ap- Author contributions: Panda A and Gamanagatti S contributed proach to skeletal dysplasias, reviews the essential equally to conception, article design, literature search, article radiographic features of various non-lethal epiphyseal, drafting, critical revision and image preparation; Jana M helped with the article concept, revision literature search and image metaphyseal, diaphyseal, osteopenic and sclerosing preparation; Gupta AK helped in images procurement, prepara- dysplasias and also describes features to differentiate tion and final approval of version of article to be published. these entities from other similar dysplasias. In summa- Correspondence to: Shivanand Gamanagatti, Additional ry, working algorithms for diagnosis of common skeletal Professor, Department of Radiodiagnosis, All India Institute dysplasias have also been provided. of Medical Sciences, Room no 81-B, Ansari Nagar, New Delhi 110029, India. [email protected] Telephone: +91-986-8658057 Fax: +91-986-8398508 Panda A, Gamanagatti S, Jana M, Gupta AK. Skeletal dysplasias: Received: May 16, 2014 Revised: July 2, 2014 A radiographic approach and review of common non-lethal skel- Accepted: August 27, 2014 Published online: October 28, 2014 etal dysplasias. World J Radiol 2014; 6(10): 808-825 Available from: URL: http://www.wjgnet.com/1949-8470/full/v6/i10/808. htm DOI: http://dx.doi.org/10.4329/wjr.v6.i10.808 Abstract Skeletal dysplasias are not uncommon entities and a INTRODUCTION radiologist is likely to encounter a suspected case of dysplasia in his practice. The correct and early diagno- Skeletal dysplasias also termed as osteochondrodysplasias are sis of dysplasia is important for management of compli- a large heterogeneous group of disorders comprising cations and for future genetic counselling. While there of abnormalities of bone or cartilage growth or texture. is an exhaustive classification system on dysplasias, it is They occur due to genetic mutations and their phenotype important to be familiar with the radiological features of continues to evolve throughout life. Skeletal dysplasias common dysplasias. In this article, we enumerate a ra- thus differ from dysostoses which are malformations of diographic approach to skeletal dysplasias, describe the single or multiple bones in combination, are due to ab- essential as well as differentiating features of common normal blastogenesis in-utero and phenotypically remain non-lethal skeletal dysplasias and conclude by present- static throughout life[1]. Currently more than 450 different ing working algorithms to either definitively diagnose a entities have been described based on radiologic, molecu- particular dysplasia or suggest the most likely differen- [2] tial diagnoses to the referring clinician and thus direct lar and biochemical criteria . While certain dysplasias further workup of the patient. individually are quite rare, their overall prevalence as a group has been reported to be 2.3-7.6 per 10000 births [3-6] © 2014 Baishideng Publishing Group Inc. All rights reserved. in various epidemiologic studies . However the actual prevalence may even be higher as concluded by these Key words: Skeletal dysplasia; Short limb dwarfism; Rhi- studies. zomelia; Radiograph; Skeletal survey; Review; Spondy- Some dysplasias are lethal in perinatal period and are WJR|www.wjgnet.com 808 October 28, 2014|Volume 6|Issue 10| Panda A et al . Radiographic approach to common skeletal dysplasias Table 1 Set of radiographs obtained in a skeletal survey[1] Table 2 Dysplasias with involvement of axial skeleton Skull (AP and lateral) Location Examples Thoracolumbar spine (AP and lateral) Skull Achondroplasia, Cleidocranial dysplasia Chest (AP) Mandible Pyknodysostosis Pelvis (AP) Clavicle Cleidocranial dysplasia One upper limb (AP) Ribs Asphyxiating thoracic dysplasia, Thanatophoric dysplasia One lower limb (AP) Spine Spondyloepiphyseal dysplasia congenita, Left hand (AP) ( for bone age) Mucopolysaccharidoses Pelvis Achondroplasia AP: Anteroposterior. detected on antenatal ultrasound scans while the non- plates. There may also be abnormal vertebral hooking lethal dysplasia present early in infancy or childhood with or beaking which are characteristic for certain dysplasias disproportionate short stature, failure of linear growth or (central beaking in Morquio’s syndrome, posterior hump- with other physical deformities. shaped vertebrae in spondyloepiphyseal dysplasia tarda). The appropriate diagnosis of a dysplasia is dependent The appendicular skeleton has to be assessed for (1) upon the integration of clinical and family history, physi- type of bone shortening and (2) location of abnormality, cal examination, radiologic examination and molecular i.e., epiphyseal, metaphyseal or diaphyseal. Shortening of and biochemical tests. Among these, a radiologic evalu- the limbs can be (1) rhizomelic (involving proximal parts ation is an integral part of the diagnostic workup of a of limb, i.e., humerus and femur); (2) mesomelic (involving dysplasia. A general radiologist will often encounter a middle parts of limb, i.e., radius/ulna; tibia/fibula); (3) set of radiographs of a patient with a suspected skeletal acromelic (involving hands and feet); or (4) micromelic (gen- dysplasia. While some dysplasias can be easy to diagnose eralised shortening of entire limb). based on certain characteristic or so-called “text-book” Location of abnormality can be purely epiphyseal findings, it is also important to have an appropriate ap- involving only the epiphyses, metaphyseal involving the proach to diagnosis. Thus in this article, we review the metaphyses or diaphyseal involving only the diaphyses or radiologic approach to the diagnosis of a non-lethal dys- there can be concomitant involvement of more than one plasia and thereafter describe the radiologic features of a location in appendicular skeleton. The involvement of few important and more common non-lethal dysplasias. appendicular skeleton has been summarised in Table 3. In addition, look at the bone density (decreased in os- teopenic and increased in sclerosing dysplasias respective- RADIOLOGIC EVALAUTION ly) and for an abnormal shape of bone (e.g., champagne The radiologic evaluation begins with a complete skeletal glass pelvis in achondroplasia). survey ideally comprising of a set of radiographs out- Thirdly, complications are invariable sequelae of lined in Table 1. dysplasias because of altered bone shapes. An analysis In cases with epiphyseal irregularity or stippling, it is of complications can also give a clue to the underlying recommended to obtain radiographs of both sides up- diagnosis. Epiphyseal dysplasias lead to premature osteo- per and lower limbs. Also, because dysplasias continue to arthritis and deformities like coxa vara and genu valga. phenotypically evolve throughout life, serial radiographs Spondylo-dysplasias lead to early kyphoscoliosis while are recommended and comparison should always be fractures are typically noted in dysplasias with altered made with previous radiographs to assess evolution of bone density like osteogenesis imperfecta and osteope- disease and complications[1]. It is also recommended to trosis. obtain radiographs early in childhood since the optimal age for recognition of most dysplasias is before the oblit- COMMON RADIOLOGICAL GROUPINGS eration of growth cartilage. Later when there is epiphy- seal fusion and growth ceases, the recognition of many After analysis of the skeletal survey, the radiologic find- dysplasias becomes difficult and even impossible[7]. ings can be further grouped into common radiographic Offiah and Hall[1], in their excellent article have enumer- groups. These radiographic groups have been created ated the ABCs of evaluation, comprising of anatomical based on common X-ray findings. Within these radiologi- localisation, analysis of bones and assessment of complica- cal groups are dysplasias groups conforming to that X-ray tions. Anatomically, the abnormalities can be located in the appearance and within the dysplasia groups we have axial skeleton (Table 2) or in the appendicular skeleton. enumerated a few common entities. We have basically de- In axial skeleton skull and spine are most commonly rived and modified these groups from the 2010 revision involved. The skull can either be large (achondropla- of the Nosology and Classification of Genetic Skeletal sia) or can have multiple wormian bones (cleidocranial Disorders framed by the International Skeletal Dysplasia [2,8] [9,10] dysplasia). Involvement of spine is commonly in the Society and from atlases of bone dysplasias . By form of flattening and decreased vertebral body height using these groups, we generate radiological differential termed as platyspondyly or there can be irregularity