Pathogenesis and treatment of a giant occipital bone defect with meningoencephalocele in an NF1 child: case report and review of the literature

Autosomal dominantly inherited neurofibromatosis type I (NF1) is a systemic disorder caused by a mutation of a gene on chromosome 17q11.2 and characterized by multiple café-au-lait spots, lentiginous macules, Lisch nodules of the iris, and tumors of the nervous system. Bony manifestations such as scoliosis, dysplasia of the greater sphenoidal wing, tibial pseudoarthrosis, short stature, and macrocephaly have been reported in approximately 50% of patients. However, calvarial bone defects are rare. After screening 324 articles, 23 cases (12 adult and 11 pediatric patients) of occipital bone defects in NF1 patients were selected. All patients had a single/multiple bone defect over the lambdoid suture. Adjacent benign plexiform neurofibromas were observed in 14 patients (60.8%, 7 adults and 7 children); one adult patient was diagnosed with neurofibrosarcoma. Meningoencephalocele over the occipital defect was noted in 8 cases (34.78%, all adults). Cranioplasty was performed in only 17.39% of patients. Histologic examination was performed in 7 of the 15 patients with associated neurofibromas/neurofibrosarcomas. Biopsy of the bone margins surrounding the defect was performed in only one case. Pathologic examination of the herniated parieto-occipital or cerebellar tissue was not performed in any of the patients studied. We report the case of a 9-year-old girl with NF1 and a significant occipital bone defect and performed a systematic review of the relevant literature to highlight the challenges in treating this condition and to investigate the underlying mechanisms contributing to bone defects or dysplasia in NF1.

Dental characteristics of patients with four different types of skeletal dysplasias

OBJECTIVE

Skeletal dysplasia (SD) comprises more than 450 separate disorders. We hypothesized that their dental features would be distinctive and investigated the tooth characteristics of four patients with different SDs.

MATERIAL AND METHODS

Four SD patients with molecularly confirmed diagnoses, Pt-1 acromicric dysplasia, Pt-2 hypophosphatasia and hypochondroplasia, Pt-3 cleidocranial dysplasia, and Pt-4 achondroplasia, were recruited. A tooth from each patient was evaluated for mineral density (micro-computerized tomography), surface roughness (surface profilometer), microhardness, mineral contents (energy-dispersive X-ray), and ultrastructure (scanning electron microscopy and histology), and compared with three tooth-type matched controls.

RESULTS

Pt-1 and Pt-3 had several unerupted teeth. Pt-2 had an intact-root-exfoliated tooth at 2 years old. The lingual surfaces of the patients' teeth were significantly smoother, while their buccal surfaces were rougher, than controls, except for Pt-1's buccal surface. The patients' teeth exhibited deep grooves around the enamel prisms and rough intertubular dentin. Pt-3 demonstrated a flat dentinoenamel junction and Pt-2 had an enlarged pulp, barely detectable cementum layer, and ill-defined cemento-dentinal junction. Reduced microhardnesses in enamel, dentin, and both layers were observed in Pt-3, Pt-4, and Pt-1, respectively. Pt-1 showed reduced Ca/P ratio in dentin, while both enamel and dentin of Pt-2 and Pt-3 showed reduced Ca/P ratio.

CONCLUSION

Each SD has distinctive dental characteristics with changes in surface roughness, ultrastructure, and mineral composition of dental hard tissues.

CLINICAL RELEVANCE

In this era of precision dentistry, identifying the specific potential dental problems for each patient with SD would help personalize dental management guidelines.

Biochemistry and pathophysiology of the Transient Potential Receptor Vanilloid 6 (TRPV6) calcium channel

TRPV6 is a Transient Receptor Potential Vanilloid (TRPV) cation channel with high selectivity for Ca²⁺ ions. First identified in 1999 in a search for the gene which mediates intestinal Ca²⁺ absorption, its far more extensive repertoire as a guardian of intracellular Ca²⁺ has since become apparent. Studies on TRPV6-deficient mice demonstrated additional important roles in placental Ca²⁺ transport, fetal bone development and male fertility. The first reports of inherited deficiency in newborn babies appeared in 2018, revealing its physiological importance in humans. There is currently strong evidence that TRPV6 also contributes to the pathogenesis of some common cancers. The recently reported association of TRPV6 deficiency with non-alcoholic chronic pancreatitis suggests a role in normal pancreatic function. Over time and with greater awareness of TRPV6, other disease-associations are likely to emerge. Powerful analytical tools have provided invaluable insights into the structure and operation of TRPV6. Its roles in Ca²⁺ signaling and carcinogenesis, and the use of channel inhibitors in cancer treatment are being intensively investigated. This review first briefly describes the biochemistry and physiology of the channel, and analytical methods used to investigate these. The focus subsequently shifts to the clinical disorders associated with abnormal expression and the underlying pathophysiology. The aims of this review are to increase awareness of this channel, and to draw together findings from a wide range of sources which may help to formulate new ideas for further studies.

Achondroplasia: Update on diagnosis, follow-up and treatment

Achondroplasia requieres multidisciplinary follow-up, with the aim of preventing and managing complications, improving the quality of life of people who suffer from it and favoring their independence and social inclusion. This review is justified by the multiple publications generated in recent years that have carried out a change in its management. Different guidelines and recommendations have been developed, among which the one made by the American Academy of Pediatrics in 2005 recently updated (2020), the Japanese guide (2020), the first European Consensus (2021) and the International Consensus on the diagnosis, approach multidisciplinary approach and management of individuals with achondroplasia throughout life (2021). However, and despite these recommendations, there is currently a great worldwide variability in the management of people with achondroplasia, with medical, functional and psychosocial consequences in patients and their families. Therefore, it is essential to integrate these recommendations into daily clinical practice, taking into account the particular situation of each health system.

An ultra-rare case of immunoskeletal dysplasia with neurodevelopmental abnormalities in an Indian patient with homozygous c.953C > T variant in EXTL3 gene: a case report

Background

Immunoskeletal dysplasia with neurodevelopmental abnormalities (ISDNA) is an ultra-rare genetic condition that belongs to the group of spondyloepimetaphyseal dysplasias. It is caused due to presence of biallelic variants in the EXTL3 gene. The encoded exostosin like glycosyltransferase 3 (EXTL3) protein plays a key role in heparan sulfate synthesis. The skeletal and nervous systems are prominently affected in ISDNA with variability in immunological manifestations. Here, we report the 15^th case of ISDNA (third patient of an Indian ancestry) in the world, along with a review of literature.

Case presentation

A 15-month-old female child with clinical indications of global developmental delay, short stature, coarse facial features, and hypotonia was referred to our clinic. Spondyloepimetaphyseal dysplasias associated with extra-skeletal manifestations was suspected based on clinic-radiological correlation. Whole exome sequencing analysis revealed the presence of a homozygous known pathogenic variant c.953C > T (p. Pro318Leu) in exon 3 of the EXTL3 gene, thereby confirming diagnosis of ISDNA.

Conclusion

We present an ultra-rare case of ISDNA- third patient of Indian ancestry and only the 15^th reported case in the literature. On review of all cases in the literature, we find that the affected individuals show abnormalities primarily in three systems namely- skeletal, nervous and immune system. Notably, patients harbouring the same variant in EXTL3 gene show phenotypic variability especially with respect to presence or absence of immunological manifestations, suggesting a role of unknown modifiers. Hence, it is currently not possible to correlate the variant position in the EXTL3 gene with disease severity.

Familial florid cemento-osseous dysplasia: a report of three cases and review of the literature

Familial cases of benign fibro-osseous lesions of the jaws are rare and have been described under numerous terms including familial gigantiform cementoma, multiple cemento-ossifying fibromas, sclerotic cemental masses and familial florid cemento-osseous dysplasia. The synonymous and interchangeable use of these terms to describe distinct entities with overlapping features has resulted in confusion and inaccurate categorisation of these lesions. This study highlights three family members with diffuse fibro-osseous jaw lesions with areas of significant expansion. In the pursuit of finding the best clinicopathological categorisation for the reported cases, familial florid cemento-osseous dysplasia and familial gigantiform cementoma were investigated. The final consensus of these three cases was that of familial florid cemento-osseous dysplasia, and one patient presented with a concurrent "ossifying fibromatoid lesion". A literature review on the above entities was performed in an attempt to provide clarification and delineate distinguishing features of the individual diseases.

Skeletal ciliopathies: a pattern recognition approach

Ciliopathy encompasses a diverse group of autosomal recessive genetic disorders caused by mutations in genes coding for components of the primary cilia. Skeletal ciliopathy forms a subset of ciliopathies characterized by distinctive skeletal changes. Common skeletal ciliopathies include Jeune asphyxiating thoracic dysplasia, Ellis-van Creveld syndrome, Sensenbrenner syndrome, and short-rib polydactyly syndromes. These disorders share common clinical and radiological features. The clinical hallmarks comprise thoracic hypoplasia with respiratory failure, body disproportion with a normal trunk length and short limbs, and severely short digits occasionally accompanied by polydactyly. Reflecting the clinical features, the radiological hallmarks consist of a narrow thorax caused by extremely short ribs, normal or only mildly affected spine, shortening of the tubular bones, and severe brachydactyly with or without polydactyly. Other radiological clues include trident ilia/pelvis and cone-shaped epiphysis. Skeletal ciliopathies are commonly associated with extraskeletal anomalies, such as progressive renal degeneration, liver disease, retinopathy, cardiac anomalies, and cerebellar abnormalities. In this article, we discuss the radiological pattern recognition approach to skeletal ciliopathies. We also describe the clinical and genetic features of skeletal ciliopathies that the radiologists should know for them to play an appropriate role in multidisciplinary care and scientific advancement of these complicated disorders.

Osteoma-like melorheostosis: a rare type of skeletal dysplasia depicted on FDG PET/CT

Melorheostosis, also known as Leri's disease, is a rare benign form of mesodermal mixed sclerosing bone dysplasia. We report the unusual case of a 14-year-old boy with melorheostosis in the lower extremity that went undiagnosed due to concurrent Ewing sarcoma in the opposite limb, confounding the findings for metastatic disease. The diagnosis was made on FDG PET/CT when the patient presented for post Ewing sarcoma treatment follow-up. The different types of melorheostosis as well as the challenge of diagnosing this rare entity are discussed in this report.

Otosclerosis and Dysplasias of the Temporal Bone

Many bone dysplasias, some common and others rare, may involve the temporal bone causing conductive, sensorineural, or mixed hearing loss, vestibular dysfunction, or skull base foraminal narrowing, potentially affecting quality of life. Some conditions may affect only the temporal bone, whereas others may be more generalized, involving different regions of the body. High-resolution computed tomography may detect subtle osseous changes that can help define the type of dysplasia, and MR imaging can help define the degree of activity of lesions and potential associated complications.

Melorheostosis: a Rare Sclerosing Bone Dysplasia

PURPOSE OF REVIEW

Melorheostosis is a rare sclerosing bone dysplasia that affects both cortical bone and adjacent soft tissue structures in a sclerotomal distribution. In this review, we describe the natural history, radiological features, proposed pathogenesis, and management options for this debilitating condition.

RECENT FINDINGS

Since its first description in 1922, about 400 cases of melorheostosis have been reported, either as single reports or in small case series. Melorheostosis affects the appendicular skeleton more commonly than the axial skeleton and usually presents with lower limb deformity. Diagnosis is based on a combination of clinical and radiological features that help differentiate this condition from other sclerosing bone dysplasias. LEM domain-containing protein 3 (LEMD3) gene mutations have been demonstrated in several familial cases, but these have been more strongly correlated with other hereditary dysplasias, such as osteopoikilosis, and are not thought to be the causative gene for melorheostosis. The exact etiology of classic sporadically occurring melorheostosis remains unknown, with possible causes being somatic LEMD3 mutations, somatic mutations in the bone morphogenetic protein/transforming growth factor-beta pathway, mutations in multiple genes, or other non-genetic causes. Management in recent years has involved nitrogen-containing bisphosphonates in addition to traditional orthopedic surgical approaches and physical therapy. Melorheostosis may present as mixed or atypical osseous involvement in addition to the classically described "dripping candle wax" appearance of hyperostosis. Some patients may have overlap with osteopoikilosis or Buschke-Ollendorff syndrome. In the future, better characterization of genetic and developmental factors predisposing to melorheostosis may lead to the development of targeted therapy for this condition, as well as for more commonly encountered skeletal abnormalities.

[Custom-made implant for complex facial reconstruction: A case of total replacement of temporo-mandibular joint, zygomatic arch and malar bone]

INTRODUCTION

Total prosthetic replacement of the temporo-mandibular joint (TMJ) has become a common procedure, but it is usually limited to the TMJ itself. We report about one case of complex prosthetic joint reconstruction extending to the neighbouring bony structures.

CASE

A 57-year-old patient, operated several times for a cranio-facial fibrous dysplasia, presented with a recurring TMJ ankylosis and a complexe latero-facial bone loss on the right side. We performed a reconstruction procedure including the TMJ, the zygomatic arch and the malar bone by mean of custom made composite prosthesis (chrome-cobalt-molybdenum-titanium and polyethylene). Five years postoperatively, mouth opening, nutrition, pain and oral hygiene were significantly improved.

DISCUSSION

Nowadays technical possibilities allow for complex facial alloplastic reconstructions with good medium term results.

Low-dose computed tomography to diagnose fetal bone dysplasias

We present a case of cleidocranial dysplasia diagnosed by low-dose fetal computed tomography (CT) in the 25th week of gestation. Severe bone dysplasia was suspected because of the fetus' low percentile in long bones length and the appearance of craniosynostosis on sonography. CT found no abnormalities incompatible with life. The effective dose was 5 mSv, within the recommended range for this type of examination. Low-dose fetal CT is a new technique that makes precision study of the bony structures possible from the second trimester of pregnancy. In Spain, abortion is legal even after the 22nd week of gestation in cases of severe fetal malformations. Therefore, in cases in which severe bone dysplasia is suspected, radiologists must know the strategies for reducing the dose of radiation while maintaining sufficient diagnostic quality, and they must also know which bony structures to evaluate.

Melorheostosis of the Foot: A Case Report of A rare entity with a Review of Multimodality Imaging Emphasizing the Importance of Conventional Radiography in Diagnosis

Introduction:

Melorheostosis is a benign bone dysplasia affecting predominantly the appendicular skeleton and adjoining soft tissues. The diagnosis can be established on plain radiographs alone and advanced imaging modalities can be avoided. We hereby report a rare case of melorheostosis affecting the foot with a review of the role of various imaging modalities in diagnosis of this rare bone dysplasia.

Case Report:

We present the case of a 29 years old man who was diagnosed with melorheostosis affecting his left foot. The patient presented to the outpatient department of our tertiary care referral hospital with complains of pain in the left ankle and foot with imaging and evaluation done at a primary center. The radiograph revealed an irregular, longitudinal extraosseous hyperostosis along the body of the calcaneum and the metacarpals which was consistent with the classical radiological description of melorheostosis. The CT, MRI and bone scan findings corroborated our primary diagnosis.

Conclusion:

The purpose of this case report is to review the features of this rare disorder affecting the foot, on multiple imaging modalities and emphasizing the role of conventional radiology in its diagnosis.

Biomechanics of walking in adolescents with progressive pseudorheumatoid arthropathy of childhood leads to physical activity recommendations as therapeutic focus

BACKGROUND

Progressive pseudorheumatoid arthropathy of childhood is a rare disease with an estimated prevalence of approximately 1/1,000,000. The disease manifests around the age of three to eight years and progresses with symptoms of early fatigue, muscle weakness, joint swelling and stiffness. The resulting functional limitations are often described as having a waddling gait. Walking is difficult and can be managed with multilevel compensation movements only. Aims of this study were to determine typical malpositions that arise during walking and to identify preventive strategies to reduce excessive joint damage.

METHODS

This study presents data of three-dimensional gait analysis of nine patients with progressive pseudorheumatoid arthropathy of childhood (♀=2; ♂=7; 13.3y; 47.0kg; 1.39m; BMI: 24.2kg/m(2)) performed with eight infrared cameras and the Plug-in-Gait Model. For comparison of spatiotemporal and kinematic parameters with age-matched healthy controls (♀=6; ♂=3; 13.4y; 49.0kg; 1.61m; BMI: 18.9kg/m(2)), the Mann-Whitney U-test was applied with a significance level of P<0.05.

FINDINGS

The patients had a significantly lower height, but higher BMI. Walking speed was reduced with wide, but short steps and significant motion anomalies in the pelvis, hips, knees and ankles. Small ranges of motion in propulsion-supporting movements were typical, especially in the sagittal plane. The gait analysis revealed dominant compensatory movements in pelvic obliquity and rotation.

INTERPRETATION

The deficits can be attributed to pronounced muscle weakness plus functional joint impairment and pain. Therapeutic preventive strategies therefore should consider continuous muscle power exercises, stretching programmes and restrictive weight control.

Pycnodysostosis: A bone dysplasia with unusual oral manifestation

Pycnodysostosis, a sclerosing bone dysplasia, is a rare autosomal recessive disorder with an estimated prevalence rate of one in one million. Patients with pycnodyostosis usually have normal intelligence, sexual development and life span. This condition is characterized by increased bone density and fragility along with oral manifestations like malposition teeth, hypoplastic maxilla, receded chin and delayed eruption of permanent teeth with discharging sinuses in the jaws because of poor blood supply. This is one such rare case report of a 47-year-old patient presenting with a complaint of fractured jaw and reviewing the clinical and radiographic characteristics of pycnodysostosis.

Sclerosing bone dysplasias with involvement of the craniofacial skeleton

In this review we provide a complete overview of the existing sclerosing bone dysplasias with craniofacial involvement. Clinical presentation, disease course, the craniofacial symptoms, genetic transmission pattern and pathophysiology are discussed. There is an emphasis on radiologic features with a large collection of CT and MRI images. In previous reviews the craniofacial area of the sclerosing bone dysplasias was underexposed. However, craniofacial symptoms are often the first symptoms to address a physician. The embryology of the skull and skull base is explained and illustrated for a better understanding of the affected areas.