Focal Benign Disorders of the Pediatric Mandible With Radiologic-Histopathologic Correlation: Mandibular Development and Lucent Lesions.

OBJECTIVE: Lucent lesions of the pediatric mandible may present variably. Cysts, neoplasms, and developmental and inflammatory conditions have a host of possible causes. There is also substantial overlap in the imaging appearance of cysts and that of benign but locally aggressive tumors that need to undergo resection. CONCLUSION: The purpose of this article is to present common and uncommon lucent lesions of the mandible in children, with an emphasis on benign abnormalities. Discussions of imaging and histopathologic features are provided.

Mutations in EXOSC2 are associated with a novel syndrome characterised by retinitis pigmentosa, progressive hearing loss, premature ageing, short stature, mild intellectual disability and distinctive gestalt.

BACKGROUND: Retinitis pigmentosa in combination with hearing loss can be a feature of different Mendelian disorders. We describe a novel syndrome caused by biallelic mutations in the 'exosome component 2' (EXOSC2) gene. METHODS: Clinical ascertainment of three similar affected patients followed by whole exome sequencing. RESULTS: Three individuals from two unrelated German families presented with a novel Mendelian disorder encompassing childhood myopia, early onset retinitis pigmentosa, progressive sensorineural hearing loss, hypothyroidism, short stature, brachydactyly, recognisable facial gestalt, premature ageing and mild intellectual disability. Whole exome sequencing revealed homozygous or compound heterozygous missense variants in the EXOSC2 gene in all three patients. EXOSC2 encodes the 'ribosomal RNA-processing protein 4' (RRP4)-one of the core components of the RNA exosome. The RNA exosome is a multiprotein complex that plays key roles in RNA processing and degradation. Intriguingly, the EXOSC2-associated phenotype shows only minimal overlap with the previously reported diseases associated with mutations in the RNA exosome core component genes EXOSC3 and EXOSC8. CONCLUSION: We report a novel condition that is probably caused by altered RNA exosome function and expands the spectrum of clinical consequences of impaired RNA metabolism.

Is there a correlation between sleep disordered breathing and foramen magnum stenosis in children with achondroplasia?

Children with achondroplasia have midface hypoplasia, frontal bossing, spinal stenosis, rhizomelia, and a small foramen magnum. Central sleep apnea, with potential resultant sudden death, is thought to be related to compression of the spinal cord at the cervicomedullary junction in these patients. Screening polysomnography and/or cervical spine MRI are often performed for infants with achondroplasia. Decompressive suboccipital craniectomy has been performed in selected cases. We aim to better delineate the relationship between polysomnography, cervical spine MRI, and indications for surgical decompression in achondroplasia.We retrospectively review electronic medical records of all children with achondroplasia in our IRB-approved skeletal dysplasia registry who had received screening polysomnography and cervical spine MRI examination was performed. We explored correlations of polysomnography, MRI parameters, and need for decompressive surgery. Seventeen patients with both polysomnography and MRI of the cervical spine met inclusion criteria. The average age at time of the sleep study was 2.4 ± 3.6 years. An abnormal apnea-hypopnea index was found in all patients, with central sleep apnea found in 6/17. Five patients (29%) required foramen magnum decompression. We found no statistically significant correlation between central sleep apnea and abnormal MRI findings suggestive of foramen magnum stenosis. Screening polysomnography is an important tool but does not appear to correlate with MRI findings of foramen magnum stenosis. Cord compression, with either associated T2 cord signal abnormality or clinical findings of clonus, was most predictive of subsequent surgical decompression.

Best practices in the evaluation and treatment of foramen magnum stenosis in achondroplasia during infancy.

Achondroplasia is the most common inherited disorder of bone growth (skeletal dysplasia). Despite this fact, consistent and evidence-based management approaches to recognized, life-threatening complications, such as foramen magnum stenosis, are lacking. This study aims to outline best practice, based on evidence and expert consensus, regarding the diagnosis, assessment, and management of foramen magnum stenosis in achondroplasia during infancy. A panel of 11 multidisciplinary international experts on skeletal dysplasia was invited to participate in a Delphi process. They were: 1) presented with a list of 26 indications and a thorough literature review, 2) given the opportunity to anonymously rate the indications and discuss in face to face discussion; 3) edit the list and rate it in a second round. Those indications with more than 80% agreement were considered as consensual. After two rounds of rating and a face-to-face meeting, consensus was reached to support 22 recommendations for the evaluation and treatment of foramen magnum stenosis in infants with achondroplasia. These recommendations include indications for surgical decompression, ventriculomegaly, and hydrocephalus, sleep-disordered breathing, physical exams and the use of polysomnography and imaging in this condition. We present a consensus-based best practice guidelines consisting of 22 recommendations. It is hoped that these guidelines will lead to more uniform and structured evaluation, standardizing care pathways, and improving mortality and morbidity outcomes for this cohort.

Opsismodysplasia: Phosphate Wasting Osteodystrophy Responds to Bisphosphonate Therapy.

UNLABELLED: We present two siblings affected with opsismodysplasia (OPS), a rare skeletal dysplasia caused by mutations in the inositol polyphosphate phosphatase-like 1 gene. The skeletal findings include short stature with postnatal onset micromelia, marked platyspondyly, squared metacarpals, delayed skeletal ossification, metaphyseal cupping, and postnatal micromelia. Respiratory compromise, delayed ambulation, and progressive lower extremity deformities are described. The severity of findings is variable. Renal phosphate wasting is associated with severe bone demineralization and a more severe phenotype. This report represents the first described cases of opsismodysplasia treated with intravenous bisphosphonate (pamidronate). Surgical management for lower extremity deformities associated with OPS is also reviewed. LEVEL OF EVIDENCE: IV Case series.

Ultrasound-guided joint injections for MR arthrography in pediatric patients: how we do it.

In children, MR arthrography is typically performed using fluoroscopic guidance. This article explores the role of US-guided joint injections as an alternative for MR arthrography in children, discussing its advantages and disadvantages compared to standard methods. We describe techniques for performing US-guided injection of the shoulder, elbow, hip, knee, ankle and posterior subtalar joints, highlighting pertinent anatomy, routes of access and unique considerations for this modality in children. Written descriptions, images and links to video clips are used to illustrate proper arthrographic technique. We conclude that US provides effective guidance for intra-articular injection prior to MR arthrography, with the advantages of improved visualization of internal structures, reduced radiation exposure, convenience of performing the procedure portably and ease of performance. Although this paper does not address therapeutic steroid injections, these techniques could easily be translated for such purposes. We propose US guidance as a viable alternative to fluoroscopic technique for arthrography in children.

Vertical expandable prosthetic titanium rib (VEPTR): a review of indications, normal radiographic appearance and complications.

Vertical expandable prosthetic titanium rib (VEPTR) is increasingly used in the treatment of thoracic insufficiency, idiopathic and neuromuscular scoliosis and chest wall defects in children. In contrast to spinal fusion surgery, the VEPTR allows for growth while stabilizing the deformity. We illustrate the common indications and normal radiographic appearance of the three common configurations of VEPTR (cradle-to-cradle assembly, cradle with lumbar extension assembly, cradle-to-ala hook assembly). There is a relatively high rate of reported complications with VEPTR in the literature. We discuss the potential complications of VEPTR, including infection, rib fracture, dislodged hardware and neurological injury, with an emphasis on imaging diagnosis.

Imaging in pediatric small bowel transplantation.

Small bowel transplantation, alone or with other organs as multivisceral transplantation, is performed for patients with chronic intestinal failure. With advancing surgical techniques and improved post-surgical management, survival of these patients has increased tremendously in the last two decades. The radiologist has an important role in the preoperative and postoperative management of these patients. Knowledge of surgical techniques and post-surgical complications seen in the transplant recipient is necessary for adequate management of these patients.

Interactive digital atlas of skeletal surveys for common skeletal dysplasias.

BACKGROUND: Skeletal dysplasias are conditions of abnormal bone and cartilage growth resulting in short stature. Developing expertise in the radiographic evaluation of dysplasias can be difficult because more than 250 skeletal dysplasias have been described. Exhaustive description of individual dysplasias can be found in hard copy textbooks, without the ability to compare dysplasias side by side. OBJECTIVE: To provide radiographic images of several common skeletal dysplasias with comparative normal skeletal surveys, thus facilitating understanding of the terminology and differences in imaging appearances commonly encountered in interpreting dysplasias. MATERIALS AND METHODS: Images from skeletal surveys obtained at our institution from 2006 to 2010 were compiled and reviewed for best quality images. Selected surveys were divided into body parts. The software program used for viewing the atlas permits linked scrolling, resizing of images, and simultaneous comparison of cases. RESULTS: Radiographic images for 13 common skeletal dysplasias and 3 comparative normal skeletons (neonate, infant and child) are provided as an interactive digital atlas. CONCLUSION: The placement of images of several common skeletal dysplasias with descriptive text in an interactive and comparative format facilitates understanding of basic radiographic terminology and appearances. We describe the atlas and discuss skeletal survey interpretation.

Neonatal skeletal dysplasias.

Skeletal dysplasias are a large diverse group of disorders characterized by abnormal bone and cartilage growth. Approximately one-quarter of them are considered lethal in the perinatal period. This paper will review the components of the skeletal survey, the primary imaging tool for diagnosing dysplasias postnatally, emphasizing the use of an organized approach and appropriate descriptive terminology. Several illustrative cases of lethal and nonlethal dysplasias will be shown, with additional discussion of commonly associated genetic mutations and classification systems.

Skeletal muscle edema in muscular dystrophy: clinical and diagnostic implications.

Muscle degeneration in muscular dystrophies often includes a period of edema before fatty replacement of muscle tissue. Magnetic resonance imaging (MRI) has been used successfully to characterize muscle and fat patterns in several types of muscular dystrophies. Recent MRI techniques enable characterization of edema in tissues. This article reviews the advantages of using MRI assessment of edema and fat in muscle tissue to evaluate disease progression, and discusses inflammation and sarcolemma compromise as sources of edema in muscular dystrophy. Lastly, refining current techniques and adapting other MRI capabilities may enhance detection and assessment of edema for better evaluation of disease progression and treatment outcomes.

EXT2-positive multiple hereditary osteochondromas with some features suggestive of metachondromatosis.

Metachondromatosis (MC) and hereditary multiple osteochondromas (HMO) are thought to be distinct disorders, each with characteristic x-ray and clinical features. Radiographic differences are the current mainstay of differential diagnosis. Both disorders are autosomal dominant, but the majority of patients with HMO have mutations in EXT-1 or EXT 2 genes. The genetic defect in MC is unknown, although recent studies indicate a possible identifiable mutation. The cancer risk in HMO is thought to be greater than in MC, although the small number of cases make such conjecture imprecise. The purpose of this report is to review existing literature and examine whether radiographic findings in HMO and MC can be reliable as a stand-alone means of differential diagnosis. Three members of a multi-generational family with an autosomal dominant exostosis syndrome were studied by clinical examination and complete skeletal survey. The roentgenographic characteristics of all osteochondromas were analyzed. The father underwent gene sequencing for EXT-1 and EXT-2, which revealed a novel EXT-2 mutation. Typical radiographic and clinical findings of both HMO and MC were seen throughout the family as well as in individuals. These family study findings contradict many of the long-standing clinical and x-ray diagnostic criteria for differentiating MC from HMO. The phenotypic crossover between the two conditions in this family, and results of genetic analysis, suggest that in the absence of a definitive genetic diagnosis, radiographic and clinical diagnosis of past and future cases HMO and MC may not be as reliable as previously assumed.

Pediatric intestinal transplantation: normal radiographic appearance and complications.

We present a pictorial essay on pediatric intestinal transplantation that describes the indications for pediatric intestinal transplantation, surgical technique, and the role of imaging in the pre-transplant work-up and detection of post-transplant complications. We illustrate the normal post-transplant imaging appearance and common complications, including rejection, infection, post-transplant lymphoproliferative disease (PTLD), mechanical dysfunction and vascular complications. We conclude with an imaging algorithm for suspected post-transplant complications based on clinical scenarios.

Neuronal migration disorders in microcephalic osteodysplastic primordial dwarfism type I/III.

Microcephalic osteodysplastic primordial dwarfism (MOPD) is a rare microlissencephaly syndrome, with at least two distinct phenotypic and genetic types. MOPD type II is caused by pericentrin mutations, while types I and III appear to represent a distinct entity (MOPD I/III) with variably penetrant phenotypes and unknown genetic basis. The neuropathology of MOPD I/III is little understood, especially in comparison to other forms of lissencephaly. Here, we report postmortem brain findings in an 11-month-old female infant with MOPD I/III. The cerebral cortex was diffusely pachygyric, with a right parietal porencephalic lesion. Histologically, the cortex was abnormally thick and disorganized. Distinct malformations were observed in different cerebral lobes, as characterized using layer-specific neuronal markers. Frontal cortex was severely disorganized and coated with extensive leptomeningeal glioneuronal heterotopia. Temporal cortex had a relatively normal 6-layered pattern, despite cortical thickening. Occipital cortex was variably affected. The corpus callosum was extremely hypoplastic. Brainstem and cerebellar malformations were also present, as well as old necrotic foci. Findings in this case suggest that the cortical malformation in MOPD I/III is distinct from other forms of pachygyria-lissencephaly.

Pseudointercondylar notch sign: manifestation of osteochondritis dissecans of the trochlea.

Osteochondritis dissecans (OCD) is an idiopathic condition affecting the articular epiphysis. Initially described in the knee, this entity affects several other parts of the body such as the talar dome, tarsal navicular, and femoral capital epiphysis. OCD of the elbow primarily involves the capitellum. OCD involving the trochlea has rarely been reported. We describe an unusual and interesting case of OCD affecting the trochlea, mimicking a pseudointercondylar notch.