Paediatric Chordomas

Craniovertebral Junction Instability after Oncological Resection: A Narrative Review

The craniovertebral junction (CVJ) is a complex transition area between the skull and cervical spine. Pathologies such as chordoma, chondrosarcoma and aneurysmal bone cysts may be encountered in this anatomical area and may predispose individuals to joint instability. An adequate clinical and radiological assessment is mandatory to predict any postoperative instability and the need for fixation. There is no common consensus on the need for, timing and setting of craniovertebral fixation techniques after a craniovertebral oncological surgery. The aim of the present review is to summarize the anatomy, biomechanics and pathology of the craniovertebral junction and to describe the available surgical approaches to and considerations of joint instability after craniovertebral tumor resections. Although a one-size-fits-all approach cannot encompass the extremely challenging pathologies encountered in the CVJ area, including the possible mechanical instability that is a consequence of oncological resections, the optimal surgical strategy (anterior vs posterior vs posterolateral) tailored to the patient's needs can be assessed preoperatively in many instances. Preserving the intrinsic and extrinsic ligaments, principally the transverse ligament, and the bony structures, namely the C1 anterior arch and occipital condyle, ensures spinal stability in most of the cases. Conversely, in situations that require the removal of those structures, or in cases where they are disrupted by the tumor, a thorough clinical and radiological assessment is needed to timely detect any instability and to plan a surgical stabilization procedure. We hope that this review will help shed light on the current evidence and pave the way for future studies on this topic.

SMARCB1 Loss in Poorly Differentiated Chordomas Drives Tumor Progression

Poorly differentiated (PD) chordoma, a rare, aggressive tumor originating from notochordal tissue, shows loss of SMARCB1 expression, a core component of the Switch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complexes. To determine the impact of SMARCB1 re-expression on cell growth and gene expression, two SMARCB1-negative PD chordoma cell lines with an inducible SMARCB1 expression system were generated. After 72 hours of induction of SMARCB1, both SMARCB1-negative PD chordoma cell lines continued to proliferate. This result contrasted with those observed with SMARCB1-negative rhabdoid cell lines in which SMARCB1 re-expression caused the rapid inhibition of growth. We found that the lack of growth inhibition may arise from the loss of CDKN2A (p16INK4A) expression in PD chordoma cell lines. RNA-sequencing of cell lines after SMARCB1 re-expression showed a down-regulation for rRNA and RNA processing as well as metabolic processing and increased expression of genes involved in cell adhesion, cell migration, and development. Taken together, these data establish that SMARCB1 re-expression in PD chordomas alters the repertoire of SWI/SNF complexes, perhaps restoring those associated with cellular differentiation. These novel findings support a model in which SMARCB1 inactivation blocks the conversion of growth-promoting SWI/SNF complexes to differentiation-inducing ones, and they implicate SMARCB1 loss as a late event in tumorigenic progression. Importantly, the absence of growth inhibition after SMARCB1 restoration creates a unique opportunity to identify therapeutic vulnerabilities.

Update of pediatric bone tumors-notochordal tumors, chondrogenic tumors, and vascular tumors of the bone

There are numerous bone tumors in the pediatric population, with imaging playing an essential role in diagnosis and management. Our understanding of certain bone tumors has rapidly evolved over the past decade with advancements in next-generation genetic sequencing techniques. This increased level of understanding has altered the nomenclature, management approach, and prognosis of certain lesions. We provide a detailed update of bone tumors that occur in the pediatric population with emphasis on the recently released nomenclature provided in the 5^th edition of the World Health Organization Classification of Soft Tissue and Bone Tumours. In the current manuscript, we address notochordal tumors, chondrogenic tumors, and vascular tumors of the bone.

Paediatric gingival extra-axial chordoma: an extremely rare entity

Extra-axial chordomas are rare malignant tumours. As a subcategory of axial chordomas, these tumours arise outside the axial skeleton. This report describes the case of a 13-year-old male patient with a gingival mass in the left upper jaw, who was referred to Hannover Medical School with a preliminary diagnosis of a calcifying epithelial odontogenic tumour (CEOT). Pathological examination of the enucleated tumour led to the final diagnosis of a chordoma. Thereafter, a stepwise radical resection was performed with the aim of complete resection of the tumour with wide safety margins. The main tumour mass was found to be located on the maxillary gingiva, with focal infiltration into the maxillary bone. Following resection, reconstruction was performed with a free latissimus dorsi flap. Follow-up after 1 year revealed no signs of recurrence or metastasis. This case highlights that although extremely rare, extra-axial chordoma may occur at sites distant from the midline and as such must be included in the differential diagnosis of bone and soft tissue tumours in the maxillofacial region.

Pediatric Petrous Apex Lesions: A Radiological Classification and Diagnostic Algorithm

The petrous apex (PA) is involved in a myriad of pathological conditions, some of which are exclusive in children. Diagnosis may be difficult due to vague clinical presentation, and local examination is challenging owing to its inaccessible location. This is further complicated by multiple unfused sutures and ongoing PA pneumatization in children. Cross-sectional imaging is vital for the evaluation of the PA lesions, due to their precarious location and proximity to the major neurovascular structures. Several classification systems have been proposed for these lesions based on their site of origin, solid or cystic appearance, surgical or non-surgical (no touch lesions) management, and benign or malignant nature. In this article, we emphasize the distinctive role of different cross-sectional imaging modalities in the diagnosis of pediatric PA lesions, with special attention to normal variants that should not be mistaken for pathology. We also propose a radiological classification and algorithmic approach to aid in the precise diagnosis and facilitate appropriate management of the various PA lesions in children.

Clinical management of pediatric chordomas: a comprehensive review

Chordomas are malignant tumors derived from remnants of the notochord. These are extremely rare in pediatric patients, accounting for approximately 5% of all chordomas, with most lesions occupying the cranium. Chordomas also can occupy all levels of the spine, demonstrating a broad spectrum of neurologic presentation. Optimal treatment aims for gross total resection with accompanying radiation therapy to prevent recurrence. Their aggressive and infiltrative nature makes clinical management challenging, involving multiple disciplines and close monitoring to ensure optimal outcomes. This comprehensive review aims to cover the genetics, demographics, pathogenesis, neurologic sequelae, radiological considerations, chemotherapeutic management, surgical management, and post-operative considerations of pediatric chordoma patients.

Primary digital localization of extra-axial extra-osseous soft-tissue chordoma: A case report

We report a case of digital extra-axial extra-osseous soft-tissue chordoma located in a flexor synovial sheath of the little finger of the left hand. Histology-immunohistochemistry (brachyury) analysis after broad en-bloc resection confirmed the diagnosis. Exhaustive MRI assessment of the entire spine, skull and pelvis found no other locations. No recurrence was reported at last follow-up. Hand surgeons should be aware of the diagnosis and treatment of brachyury-positive extra-axial soft-tissue chordomas, whence the importance of recognizing its typical and differential characteristics to guide optimal therapeutic strategy.

Magnetic Resonance Imaging during Proton Therapy Irradiation Allows for the Early Response Assessment of Pediatric Chordoma

Chordoma in pediatric patients is very rare. Proton therapy has become a gold standard in the treatment of these neoplasms, as high dose escalation can be achieved regarding the target while maximizing the sparing of the healthy tissues near the tumor. The aim of the work was to assess the evolution of morphological sequences during treatment using T1/T2-weighted magnetic resonance imaging (MRI) for the early response assessment of a classic chordoma of the skull base in a pediatric patient who had undergone surgical excision. Our results demonstrated a significant quantitative reduction in the residual nodule component adhered to the medullary bulb junction, with an almost complete recovery of normal anatomy at the end of the irradiation treatment. This was mainly shown in the T2-weighted MRI. On the other hand, the classic component of the lesion was predominantly present and located around the tooth of the axis. The occipital condyles were morphologically and dimensionally stable for the entire irradiation period. In conclusion, the application of this type of monitoring methodology, which is unusual during the administration of a proton treatment for chordoma, highlighted the unexpected early response of the disease. At the same time, it allowed the continuous assessment of the reliability of the treatment plan.

A clinical approach to parasellar lesions in the transition age

Many reviews have summarised the pathology and management of the parasellar region in adult patients, although an analysis of these aspects in the transition years, from puberty onset to the age of peak bone mass, has been lacking. A comprehensive search of English-language original articles, published from 2000 to 2020, was conducted in the MEDLINE database (December 2019 to March 2020). We selected all studies regarding epidemiology, diagnosis and management of the following parasellar lesions: germinoma, craniopharyngioma, Langerhans cell histiocytosis, optic glioma, hypothalamic hamartoma, tuber cinereum hamartoma, cranial chordoma, Rathke cleft cyst, hypophysitis and hypothalamitis during the transition age from childhood to adulthood. In the present review, we provide an overview of the principal parasellar lesions occurring in the transition age. Symptoms are usually a result of the mass effect of the lesions on nearby structures, as well as anterior pituitary deficits. Diabetes insipidus occurs frequently in these patients. In this age group, pubertal developmental disorders may be more evident compared to other stages of life. Parasellar lesions in the transition age mostly include neoplastic lesions such as germinomas, hamartomas, optic gliomas, craniopharyngiomas Langerhans cell histiocytosis and chordomas, and rarely inflammatory lesions (hypophysitis, hypothalamitis). There are limited data on the management of parasellar lesions in the transition age. Endocrine evaluation is crucial for identifying conditions that require hormonal treatment so that they can be treated early to improve the quality of life of the individual patient in this complex age range. The clinical approach to parasellar lesions involves a multidisciplinary effort.

SMARCB1/INI1-deficient tumors of adulthood

The SMARCB1/INI1 gene was first discovered in the mid-1990s, and since then it has been revealed that loss of function mutations in this gene result in aggressive rhabdoid tumors. Recently, the term "rhabdoid tumor" has become synonymous with decreased SMARCB1/INI1 expression. When genetic aberrations in the SMARCB1/INI1 gene occur, the result can cause complete loss of expression, decreased expression, and mosaic expression. Although SMARCB1/INI1-deficient tumors are predominantly sarcomas, this is a diverse group of tumors with mixed phenotypes, which can often make the diagnosis challenging. Prognosis for these aggressive tumors is often poor. Moreover, refractory and relapsing progressive disease is common. As a result, accurate and timely diagnosis is imperative. Despite the SMARCB1/INI1 gene itself and its implications in tumorigenesis being discovered over two decades ago, there is a paucity of rhabdoid tumor cases reported in the literature that detail SMARCB1/INI1 expression. Much work remains if we hope to provide additional therapeutic strategies for patients with aggressive SMARCB1/INI1-deficient tumors.

The CT guided transoral approach: A biopsy technique for a poorly differentiated chordoma in a 5 year old

Mass lesions presenting at the craniocervical junction often present a unique challenge due to the complex anatomic arrangement limiting access for tissue diagnosis. The transoral approach has predominantly been used for percutaneous vertebroplasty of high cervical vertebrae with limited literature describing image guided biopsy for bony lesions in this region in the pediatric patient. We describe a technique of computed tomography guided transoral biopsy of a poorly differentiated chordoma located at the C1-C2 level in a 5-year-old child, and review this diagnosis.

Clival Chordoma: A Rare Finding in Children

Teaching point: Clival chordoma is a rare find in children, presenting as a locally destructive, T2 hyperintense, and strongly enhancing mass.

Chordoma with lung metastases at initial presentation of a pediatric patient

Chordomas are rare, slow growing malignant tumors derived from notochord remnants that can arise anywhere along the neuronal axis. Chordomas are particularly rare in patients under 20 years of age and tend to be intracranial in location, as opposed to sacrococcygeal in adults. Metastasis at initial presentation is uncommon in all age groups and is exceedingly rare in the absence of local recurrence of the primary tumor. We report a case of advanced clival chordoma with marked nasopharyngeal disease extension and lung metastases at the time of presentation in a pediatric patient.

A historical recount of chordoma

Chordoma, a rare bone tumor that occurs along the spine, has led scientists on a fascinating journey of discoveries. In this historical vignette, the authors track these discoveries in diagnosis and treatment, noting events and clinicians that played pivotal roles in our current understanding of chordoma. The study of chordoma begins in 1846 when Rudolf Virchow first observed its occurrence on a dorsum sellae; he coined the term “chordomata” 11 years later. The chordoma’s origin was greatly disputed by members of the scientific community. Eventually, Müller’s notochord hypothesis was accepted 36 years after its proposal. Chordomas were considered benign and slow growing until the early 1900s, when reported autopsy cases drew attention to their possible malignant nature. Between 1864 and 1919, the first-ever symptomatic descriptions of various forms of chordoma were reported, with the subsequent characterization of chordoma histology and the establishment of classification criteria shortly thereafter. The authors discuss the critical historical steps in diagnosis and treatment, as well as pioneering operations and treatment modalities, noting the physicians and cases responsible for advancing our understanding of chordoma.

Whole-Body MRI Virtual Autopsy Using Diffusion-weighted Imaging With Background Suppression (DWIBS) at 3 T in a Child Succumbing to Chordoma

BACKGROUND

We report the use of diffusion-weighted imaging with background suppression (DWIBS) in pediatric virtual magnetic resonance imaging (MRI) autopsy of a child who succumbed to chordoma.

CASE DESCRIPTION

A 10-year-old girl who succumbed to relapse of a chordoma underwent whole-body virtual MRI autopsy 12 hours postmortem with short Tau inversion recovery (STIR) and DWIBS on 3 T, which demonstrated the primary mass, local and cardiac invasion, and metastatic disease to the thorax, abdomen, head/neck, and musculoskeletal system.

CONCLUSIONS

Postmortem virtual MRI autopsy including DWIBS successfully demonstrated the transthoracic spread of chordoma and invasion of the heart, resulting in blood-borne metastases. Motion and respiratory artifact were not factors during virtual autopsy using DWIBS on 3 T, making ideal use of this technology.

Multicentric Chordoma in a Child

Chordomas are primary malignant bone tumors that arise in the axial skeleton, believed to originate from remnants of embryologic notochordal cell rests. Multicentric origin of chordoma is extremely rare. To our literature search, we found only three cases of multicentric chordoma in adults. We report a first case of multicentric chordoma in pediatric age group. A 14-month-old child presented with torticolis and left upper limb monoparesis, imaging showed expansile bony destructive lesion in clivus and dorsal spine simultaneously. The child underwent laminectomy, decompression of cord, excision of lesion, and histopathology was suggestive of chordoma. Pediatric chordomas are aggressive tumors, require multidisciplinary management with maximal safe resection followed by radiotherapy (conventional and/or proton). Even with multidisciplinary management, pediatric chordomas have high morbidity and mortality.

Fifty-four-month survival in a 3-year-old child presenting with an aggressive metastatic dedifferentiated clival chordoma

Dedifferentiated chordoma is a rare, aggressive, chemoresistant and radioresistant malignancy arising from notochord remnants that can occur anywhere along the spine. Incidence in patients under 20 years of age is 1 per 250 million. We report a case of dedifferentiated clival chordoma presenting in a 3-year-old boy with pulmonary metastasis, which responded unusually well to chemotherapy, achieving complete metastatic clearance and debulking of the primary tumour. Proton beam therapy achieved further tumour control, with excellent quality of life for multiple years. On disease relapse, an atypical lateral transcondylar surgical approach achieved complete macroscopic clearance but there was cutaneous seeding. This, and continued primary site activity, failed to be controlled with targeted therapy, traditional chemotherapy and photon radiation, resulting in gradual neurological decline and death. Intensive management resulted in above-average survival despite diagnosis late in the disease course, which may be of value directing investigation into optimal management.