Primary Intracranial Rhabdomyosarcoma in the Cerebellopontine Angle Resected After Preoperative Embolization

Advances in Imaging Modalities for Pediatric Brain and Spinal Cord Tumors

BACKGROUND

Neuroimaging has evolved from anatomical imaging toward a multi-modality comprehensive anatomical and functional imaging in the past decades, important functional data like perfusion-weighted imaging, permeability imaging, diffusion-weighted imaging (DWI), and diffusion tensor imaging (DTI), tractography, metabolic imaging, connectomics, event-related functional imaging, resting state functional imaging, and much more is now being offered.

SUMMARY

Precision diagnostics has proven to be essential for precision treatment. Many minimal invasive techniques have been developed, taking advantage of digital subtraction angiography and interventional neuroradiology. Furthermore, intraoperative CT and/or MRI and more recently MR-guided focused ultrasound have complemented the diagnostic and therapeutic armamentarium.

KEY MESSAGES

In the current manuscript, we discuss standard imaging sequences including advanced techniques like DWI, DTI, susceptibility-weighted imaging, and 1H magnetic resonance spectroscopy, various perfusion weighted imaging approaches including arterial spin labeling, dynamic contrast enhanced imaging, and dynamic susceptibility contrast imaging. Pre-, intra, and postoperative surgical imaging including visualize imaging will be discussed. The value of connectomics will be presented for its value in neuro-oncology. Minimal invasive therapeutic possibilities of interventional neuroradiology and image-guided laser ablation and MR-guided high-intensity-focused ultrasound will be presented for treatment of pediatric brain and spinal cord tumors. Finally, a comprehensive review of spinal cord tumors and matching neuropathology has been included.

A rare presentation of a bilateral intracranial parameningeal embryonal rhabdomyosarcoma mimicking vestibular schwannoma in a two-year-old child: a case report

Intracranial parameningeal rhabdomyosarcomas are rare, aggressive, rapidly progressive paediatric malignancies that carry a poor prognosis. The authors report a case of a 2-year-old boy who initially presented with a left facial palsy, ataxia and, shortly after, bloody otorrhoea. MRI imaging was initially suggestive of a vestibular schwannoma. However, there was rapid progression of symptoms and further MRI imaging showed very rapid increase in tumour size with mass effect and development of a similar tumour on the contralateral side. A histological diagnosis of bilateral parameningeal embryonal rhabdomyosarcoma was made. Despite treatment, progression led to hydrocephalus and diffuse leptomeningeal disease, from which the patient did not survive. Few intracranial parameningeal rhabdomyosarcomas have previously been reported and these report similar presenting symptoms and rapid disease progression. However, this is the first reported case of a bilateral intracranial parameningeal embryonal rhabdomyosarcoma which, on initial presentation and imaging, appeared to mimic a vestibular schwannoma.

Metastatic primary brain rhabdomyosarcoma in a pediatric patient: illustrative case

BACKGROUND

Primary intracranial rhabdomyosarcoma is an extraordinarily rare malignant tumor, with even fewer presenting with distant metastasis. To date, only five cases, including the one presented here, have been reported to present metastatic activity.

OBSERVATIONS

A 12-year-old boy presented with a few days of headache, nausea, vomiting, but no neurological deficit. Brain computed tomography and magnetic resonance imaging demonstrated hydrocephalus and a cystic lesion with left parieto-occipital extension. After resection, pathology reported primary rhabdomyosarcoma, with positive desmin and myogenin on immunohistochemistry. The patient presented with pulmonary metastasis. The patient had an overall survival of 21 months after diagnosis with optimal treatment.

LESSONS

Rhabdomyosarcoma is a malignant neoplasm arising from undifferentiated skeletal muscle cells, with morphological, immunohistochemical, ultrastructural, or molecular genetic evidence of primary skeletal muscle differentiation. It presents with a rapidly worsening clinical course and the final outcome is poor. Treatment is widely based on protocols that have been proven to be effective in extracranial versions of these tumors, although repeatedly ineffective. Primary brain rhabdomyosarcoma poses a diagnostic challenge because of its infrequent presentation, grade of undifferentiation and tumor heterogeneity. Immunohistochemical and genetic testing have proven to be useful tools for diagnosis.

A case of primary CNS embryonal rhabdomyosarcoma with PAX3-NCOA2 fusion and systematic meta-review

PURPOSE

Primary central nervous system (CNS) rhabdomyosarcoma is a rare mesenchymal tumor predominantly seen in children and associated with a poor outcome. We report a case of primary CNS rhabdomyosarcoma with PAX3-NCOA2 fusion and present a systematic meta-review of primary CNS rhabdomyosarcoma to characterize this rare tumor.

METHODS

We present the case of a 6-year-old boy with primary CNS rhabdomyosarcoma in the posterior fossa. In a systematic meta-review, we compare the demographic data of primary CNS rhabdomyosarcoma with data of rhabdomyosarcoma at all sites from the SEER database and analyze clinical factors associated with survival outcome.

RESULTS

Our patient underwent gross total resection and received vincristine, actinomycin-D, cyclophosphamide with early introduction of concurrent focal radiation and remained alive with no evidence of disease for 2 years after the end of therapy. Histopathological review revealed embryonal-type rhabdomyosarcoma, and whole-transcriptome analysis revealed PAX3 (EX6)-NCOA2 (EX12) fusion. In all, 77 cases of primary CNS rhabdomyosarcoma were identified through the meta-review. The demographic data of primary CNS rhabdomyosarcoma were similar to data of rhabdomyosarcoma at all sites. Overall and event-free survival outcomes were available for 64 and 56 patients, respectively, with a 3-year OS of 29.0% and a 3-year EFS of 25.7%. The group that received trimodal treatment exhibited better survival outcomes, with a 3-year OS of 57.4% and a 3-year EFS of 46.3%.

CONCLUSIONS

Primary CNS rhabdomyosarcoma shares common histological, molecular, and demographic features with non-CNS rhabdomyosarcoma. A trimodal treatment approach with early introduction of radiation therapy may result in favorable survival outcomes.

Pterygovaginal artery as a target of embolization before endoscopic skull base surgery

BACKGROUND

The pterygovaginal artery (PtVA), a recurrent branch of the internal maxillary artery (IMA), can be a feeder of skull base tumors. Preoperative embolization can help endoscopic resection of hypervascular lesions, which is performed under a narrow surgical space with restricted instrumental maneuverability.

METHODS

We performed preoperative embolization in five cases with hypervascular skull base lesions supplied by the PtVA, four of which were resected via endoscopic endonasal approach. In two cases, selective PtVA embolization through the distal IMA was successfully conducted.

RESULTS

In all the cases, intraoperative bleeding during endoscopic resection was easily controlled. The medial and lateral origins of the PtVA from the IMA were demonstrated by cone-beam CT images reconstructed from three-dimensional rotational angiography, and anastomoses around the eustachian tube and soft palate were visualized by superselective angiography.

CONCLUSIONS

The PtVA embolization can be an effective strategy before endoscopic skull base tumor resection. When embolizing through the PtVA, clinicians should be aware of its anatomical variations and dangerous anastomoses. Understanding the surrounding angioarchitecture by angiographic techniques helps ensure safe embolization.

Cone-Beam Computed Tomography Fusion Technique for Vascular Assessment of Skull Base Meningiomas

OBJECTIVE

Cone-beam computed tomography (CBCT) images for skull base tumors provide detailed vascular information and localization in regard to surrounding bony structures. We report use of the CBCT fusion technique for skull base meningiomas.

METHODS

Six patients with petroclival or petrotentorial meningiomas supplied by multiple arterial systems were preoperatively evaluated using CBCT fusion imaging. Fusion images were reconstructed from three-dimensional rotational angiography with contrast agent injections from the internal carotid artery (ICA) and external carotid artery in 4 cases, vertebral artery and external carotid artery in 1 case, and ICA and vertebral artery in 1 case.

RESULTS

The feeding pedicles and tumor stains from 2 arterial systems were differentiated by separate colors. The courses and territories of the ICA dural feeders or ICA/vertebral artery pial feeders were easily distinguished from the external carotid artery dural feeders. Anastomoses between thin feeders from different arterial systems could be detected. Mixed stain (stain with both colors) was observed in some tumor compartments, suggesting dual supply from 2 arterial systems and the presence of peritumoral anastomoses. All patients underwent preoperative embolization without complications.

CONCLUSIONS

CBCT fusion images clearly visualized the feeders from each arterial system, the vascular compartments within the tumor, and possible peritumoral anastomoses. This technique provides a substantial contribution to both preoperative embolization and surgical resection of skull base meningiomas.

Treatment strategy and long-term outcomes of primary intracranial rhabdomyosarcoma: a single-institution experience and systematic review

OBJECTIVE

Primary intracranial rhabdomyosarcoma (PIRMS) is rare, and the effects of the treatment strategy on overall survival (OS) are unclear. This study aimed to evaluate risk factors pertinent to OS and to propose an optimal treatment strategy.

METHODS

Clinical data of patients with PIRMS treated at Beijing Tiantan Hospital and from the English-language literature between 1946 and 2018 were reviewed. A literature review was performed via Ovid, MEDLINE, Embase, PubMed, Web of Science, and Cochrane databases using the terms "rhabdomyosarcoma," "intracranial," "cerebral," and "brain." Previously published data were processed and used according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

There were 8 males (66.7%) and 4 females with PIRMS at our institution, with a mean age of 24.3 years. Gross-total resection was achieved in 4 patients (33.3%), and adjuvant radiation and chemotherapy were administered in 5 (45.5%) and 3 (27.3%) patients, respectively. After a mean follow-up period of 13.7 months, all patients developed local-regional recurrence and died of the disease. Twenty-nine cases (14 female and 15 male) were reported in the literature with a median age of 9.0 years. After a mean follow-up duration of 18.6 months, 13 patients (44.8%) developed recurrences, 7 patients (24.1%) had extracranial metastasis, and 14 patients (48.3%) died. In the pooled cases, adjuvant radiation (hazard ratio [HR] 0.089, 95% confidence interval [CI] 0.027-0.288, p < 0.001) and age < 10 years (HR 0.227, 95% CI 0.077-0.666, p = 0.007) were independent predictors of good local-regional progression-free survival (LR-PFS). Adjuvant radiation therapy (HR 0.301, 95% CI 0.110-0.828, p = 0.020) and age < 10 years (HR 0.359, 95% CI 0.131-0.983, p = 0.046) were significant predictors for favorable OS in the multivariate model.

CONCLUSIONS

Due to the rarity of the disease, a poor outcome of PIRMS was demonstrated based on the pooled cohort. Use of radiation was associated with improved outcomes and should be considered to improve OS/LR-PFS. Further study is required to identify the optimal treatment regimen.Systematic review no.: CRD42019121249 (crd.york.ac.uk/PROSPERO/).

Intracranial Rhabdomyosarcoma of the Cerebellopontine Angle in a 6-year-old Child: A Case Report

Rhabdomyosarcoma (RMS) is the most common soft-tissue malignancy in children under 15 years of age. Approximately, 35% of RMS cases originate from the head and neck region. Among various sites in the head and neck region, intracranial extension is more likely to occur with parameningeal tumors, which is also considered an unfavorable prognostic factor in children with RMS. About 20% of RMS occurs in a parameningeal site. Intracranial RMS are rare tumors that usually arise from parameningeal sites or metastasis from an extracranial site. Primary intracranial types are even rarer, with only 50 reported cases of primary intracranial RMS in the literature.

Hereby, we report the case of a 6-year-old boy who presented with clinical and radiologic features of a cerebellopontine angle lesion, which turned out to be a RMS.

Two cases of primary supratentorial intracranial rhabdomyosarcoma with DICER1 mutation which may belong to a "spindle cell sarcoma with rhabdomyosarcoma-like feature, DICER1 mutant"

Rhabdomyosarcoma is the most common soft-tissue sarcoma affecting children and adolescents. It is defined as a malignant neoplasm characterized by morphologic, immunohistochemical, ultrastructural, or molecular genetic evidence of primary skeletal muscle differentiation, usually in the absence of any other pattern of differentiation. Primary intracranial rhabdomyosarcoma (PIRMS) is an extremely rare neoplasm, with only 60 cases reported in the literature, and generally has poor prognosis with an overall survival of only 9.1 months. The DICER1 gene encodes an RNA endoribonuclease that plays a key role in gene expression regulation through the production of small RNAs. Herein, we report two cases of PIRMS with somatic DICER1 mutation showing morphological and immunohistochemical evidence of primary skeletal muscle differentiation; the two cases share common clinical features, including young age, supratentorial tumor, and onset of intratumoral bleeding. Although methylation profiling was not performed, both cases shared clinical and pathological characteristics in common with recently proposed methylation entity "spindle cell sarcoma with rhabdomyosarcoma-like features, DICER1 mutant (SCS-RMSlike-DICER1)''. Our cases provide further evidence of the link between primary intracranial sarcoma and DICER1 mutation which may form a distinct entity.