Radiological image features of the atypical teratoid/rhabdoid tumor in adults: a systematic review

Autologous stem cell transplantation in adults with atypical teratoid rhabdoid tumor: a case report and review

Aim: Atypical teratoid rhabdoid tumor (ATRT) is a rare and highly aggressive primary CNS neoplasm, predominantly observed in children. The use of autologous stem cell transplantation (ASCT) in pediatric ATRT has shown promise; however, its utility in adult ATRT remains unclear. Patients & methods: This study presents the case of an adult patient with ATRT who is in remission after ASCT and reviews the literature on ASCT in adults with ATRT. Four cases of ATRT in adults who underwent ASCT were identified, with pertinent data summarized. Results: All five patients survived longer than the historical average survival rate, four of whom had no clinical or radiographic evidence of disease at the final follow-up. Conclusion: Based on limited data, there may be a role for ASCT in the treatment of adults with ATRT.

Atypical teratoid/rhabdoid tumor in adult: case series and an integrated survival analysis

BACKGROUND

Atypical teratoid/rhabdoid tumor (AT/RT) is well documented in children but less so in adults because of its rarity.

METHOD

We report a series of five cases, a literature review and quantitative analysis of the survival outcome of adult AT/RT patients.

RESULTS

Seventy-four patients including our five cases (male: female = 16: 58) were evaluated, whose median age was 32.5 years (18-80 years). The commonest location was the sellar region. Median overall survival (OS) was 12.5 months (0.5-204.00 months). Chemotherapy was associated with OS (HR: 0.349, 95%CI: 0.176-0.694, p = 0.003), while other factors did not influence OS. From Kaplan-Meier analysis, surgery combining postoperative chemotherapy and radiotherapy was associated with better prognosis (Log Rank: χ2 = 14.662, p = 0.001).

CONCLUSIONS

Adult AT/RT is commoner in females and tends to recur rapidly after surgical resection. Chemotherapy may provide a survival benefit. Surgery combined with postoperative chemotherapy and radiotherapy was associated with better prognosis for adult AT/RT patients, though the overall prognosis was still poor.

Atypical teratoid/rhabdoid tumor of the central nervous system: Clinicopathological features of two challenging cases

INTRODUCTION

Atypical Teratoid/Rhabdoid Tumor (AT/RT) is a rare aggressive neoplasm that mainly affects the pediatric population with a peak incidence in the first two years of life and a slight male predominance, whereas presentation of this neoplasm in older ages is extremely rare.

CASE PRESENTATION

Herein, we present two cases of AT/RT. In the first case, a 9-year-old female presented with diplopia, dizziness, headache, and morning vomiting. CT Scan of the head demonstrated a heterogeneous mass in the left frontal-parietal region with vasogenic edema and midline deviation. In the second case, a 57-year-old female presented with severe generalized headache, numbness, and tingling in the right hand. MRI revealed a lobulated cystic mass in the right occipitotemporal region, with surrounding edema compressing the left lateral ventricle and causing a midline shift to the left, and enlargement of the right lateral ventricle. In both case, histopathological and immunohistochemical examinations revealed the diagnosis of Atypical teratoid/Rhabdoid tumors.

CLINICAL DISCUSSION

Microscopic examination demonstrated the proliferation of medium-sized to large cells with abundant eosinophilic cytoplasm, large vesicular eccentric nuclei, and conspicuous nucleoli with areas of necrosis and hemorrhage, thus confirming the diagnosis with adequate immunohistochemical staining. The first patient developed signs of recurrence and passed away six months later, whereas in the second case, the 57-year-old female received radiotherapy for 6 weeks before being put on chemotherapy.

CONCLUSION

Despite the challenges facing the diagnosis of this aggressive neoplasm, we managed to present our cases with detailed histopathological and immunohistochemical examinations.

Atypical Teratoid/Rhabdoid Tumor of the Nervous System in Adults: Location-Related Features and Outcome

BACKGROUND

Atypical teratoid/rhabdoid tumor (AT/RT) of the nervous system is a rare and highly malignant neoplasm, mainly affecting children, first recognized as a pathologic entity in 1996 and added to the World Health Organization Classification of the Tumors of the Central Nervous System in 2000. AT/RT is even rarer among adults and is associated with a worse prognosis. The aim of the present study was to analyze the different tumor features according to the location in adults.

METHODS

A comprehensive and detailed literature review of AT/RTs in adults was made. The demographic, management, and outcome data associated with tumor location were analyzed and compared; histopathologic and molecular features were also discussed. Furthermore, we added our personal case with brain hemispheric localization and reported a progression-free survival of 103 months after gross total resection and adjuvant radiotherapy showing a peculiar histopathologic pattern.

RESULTS

Female sex is mainly affected by AT/RT on median localizations, both intracranial and spinal, and by all sellar region cases. Gross total resection is mainly achieved among lateral compared with median localizations. Combined radiotherapy and chemotherapy is the most adopted adjuvant treatment in all tumor localizations and is related to better outcome. Postoperative death is reported only among sellar region localizations, whereas brain hemispheric cases show the best overall survival.

CONCLUSIONS

AT/RTs show different and peculiar features according to their location, which significantly affects the outcome; precise knowledge of them helps the neurosurgeon in planning the best strategy for treatment.

Atypical Teratoid Rhabdoid Tumor: Proposal of a Diagnostic Pathway Based on Clinical Features and Neuroimaging Findings

PURPOSE

To assess the main imaging and clinical features in adult- and pediatric-onset atypical teratoid rhabdoid tumor (ATRT) in order to build a predefined pathway useful for the diagnosis.

METHODS

We enrolled 11 ATRT patients (10 children, one adult) and we conducted a literature search on PubMed Central using the key terms "adult" or "pediatric" and "atypical teratoid/rhabdoid tumor". We collected clinical and neuroradiological data reported in previous studies and combined them with those from our case series. A three step process was built to reach diagnosis by identifying the main distinctive clinical and imaging features.

RESULTS

Clinical evaluation: neurological symptoms were nonspecific. ATRT was more frequent in children under 3 years of age (7 out of 10 children) and infratentorial localization was reported more frequently in children under the age of 24 months. Midline/off-midline localization was influenced by the age.

IMAGING FINDINGS

Preferential location near the ventricles and liquor spaces and the presence of eccentric cysts were hallmark for ATRT; higher frequency of peripheral cysts was detected in children and in the supratentorial compartment (five out of eight patients with solid-cystic ATRT). Leptomeningeal dissemination at diagnosis was common (5 out of 10 children), while intratumoral hemorrhage, calcifications, and high cellularity were non-specific findings. Histopathological analysis: specific immunohistochemical markers were essential to confirm the diagnosis.

CONCLUSION

In younger children, a bulky, heterogeneous mass with eccentric cystic components and development near ventricles or cisternal spaces may be suggestive of ATRT. ATRT diagnosis is more challenging in adults and relies exclusively on neuropathological examination.

Sellar Atypical Teratoid/Rhabdoid Tumors (AT/RT): A Systematic Review and Case Illustration

Introduction: Atypical Teratoid/Rhabdoid tumors are rare, highly malignant tumors in adults, with a median survival of 20 months. We report a case of a sellar atypical teratoid/rhabdoid tumor in a 70-year-old female treated with intraventricular chemotherapy, followed by a systematic review of the current management of sellar AT/RTs.

Methods: A comprehensive systematic literature search was conducted on Web of Science, Scopus, and PubMed Central using the key terms “sellar” and “atypical teratoid/rhabdoid tumors”, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data, including patient demographics, histology, treatments, and overall survival were extracted and analyzed. Kaplan-Meier survival curves and log-rank analysis were used to compare survival outcomes between different treatment regimens.

Results: Our literature search disclosed 123 publications. After prespecified exclusions, 41 patients with sellar AT/RT from 30 manuscripts were identified, and 38 were included in the final analysis. Including our patient, the median age was 44 (range: 20-70) with a substantial female predominance (94.7%). Collectively, patients who received combined chemoradiation therapy had a significantly increased overall survival compared to those who received single modality or no adjuvant therapies (median OS 27 vs. 1.25 months; p=0.0052).

Conclusion: Atypical teratoid/rhabdoid tumor in the sellar region carries a poor prognosis. Adjuvant chemotherapy and radiation therapy were associated with significantly increased overall survival. Early consideration of neuro-oncology and radiation-oncology referral and management is likely beneficial in this patient population. Intrathecal chemotherapy is a treatment modality that requires further exploration given the limited options and current dismal prognosis of adult sellar AT/RT.

Atypical teratoid/rhabdoid tumor in adults: a systematic review of the literature with meta-analysis and additional reports of 4 cases

INTRODUCTION

Atypical teratoid/rhabdoid tumor (AT/RT) is a highly aggressive embryonal CNS neoplasm, characterized by inactivation of SMARCB1 (INI1) or rarely of SMARCA4 (BRG1). While it is predominantly a childhood tumor, AT/RT is rare in adults.

METHODS

We provide a comprehensive systematic review of literature with meta-analysis; 92 adult cases were found from 74 articles. We additionally present 4 cases of adult AT/RTs (age ranging from 19 to 29 years), located to cerebellum in 2 cases, to ponto-cerebellar angle in 1 case and to spinal cord in the remaining case.

RESULTS

Microscopic features of our 4 cases showed a highly cellular tumor with rhabdoid morphology and high mitotic activity. All tumor cells lacked nuclear SMARCB1/INI1 protein expression. In case no. 3 we also performed methylation profiling which clustered the tumor with pediatric AT/RT-MYC subgroup. Prognosis remains poor in both pediatric and adult population with a median overall survival of 11 months. Our review demonstrated median overall survival of 15 months among the adult populations. However, consistent with a recent review, adult AT/RT seems to have highly variable prognosis and some patients reach long term survival with 22.9% of 5-year survival without evidence of disease and mean follow up time of 35.9 months (SD = 36.5). 27.1% of dissemination was also reported among the adult population.

CONCLUSIONS

Adult AT/RTs predominantly arise in female patients and in supratentorial location. Midline structures, including the sellar region, are the most affected sites, especially among females aged > 40 years. Male gender is more prevalent between the age of 18 and 40 years and more frequently associated with non-midline tumors. Factors significantly associated with better prognosis are patient's age (< 40 years), combined radio-chemotherapy adjuvant approach and Ki-67 score < 40%.

Primary diffuse leptomeningeal atypical teratoid rhabdoid tumor (AT/RT) demonstrating atypical imaging findings in an adolescent patient

Atypical teratoid rhabdoid tumor (AT/RT) is a highly malignant central nervous system embryonal tumor, which typically affects the posterior fossa of young children. Primary diffuse leptomeningeal AT/RT, affecting the leptomeninges without any intraparenchymal mass in the brain and spinal cord, is an extremely rare form of AT/RT. Only 5 such cases have been reported previously, none of which underwent Fluorine-18-Fluorodeoxyglucose Positron Emission Tomography (FDG-PET). We herein report a case of primary leptomeningeal AT/RT in an adolescent patient who underwent computed tomography, magnetic resonance imaging and FDG-PET. The computed tomography and magnetic resonance imaging indicated diffusely thickened leptomeninges without any intraparenchymal masses in the head and spine. Furthermore, there were multiple nodules on the thickened leptomeninges. On FDG-PET, the thickened leptomeninges and nodules demonstrated a lower standardized uptake value than that of the normal cerebral cortex. Biopsy and histopathological studies confirmed the diagnosis of AT/RT. Despite its rare occurrence, it is important to recognize primary diffuse leptomeningeal AT/RT for correct diagnosis and management of patients.

Intratumoral Hemorrhage After Endoscopic Third Ventriculostomy for Obstructive Hydrocephalus Caused by Brain Tumors

BACKGROUND

Endoscopic third ventriculostomy (ETV) for obstructive hydrocephalus and endoscopic biopsy (EB) for intraventricular and paraventricular tumors are standard therapies because they are minimally invasive procedures. Although EB-associated hemorrhagic risk has been well documented, there have been only a few reports on hemorrhagic risk associated with ETV. We conducted a single-institution retrospective study on the incidence of hemorrhage secondary to EB and/or ETV.

METHODS

We retrospectively reviewed patient characteristics, procedure, pathological findings, and complications including hemorrhage of 100 patients with intraventricular and paraventricular tumors who underwent EB and/or ETV at our institution from 2000 to 2020.

RESULTS

EB/ETV combined surgery (combined group), EB-alone surgery (EB-alone group), and ETV-alone surgery (ETV-alone group) were performed in 44 (44%), 24 (24%), and 32 (32%) patients, respectively, and all procedures were successful. The rates of definitive and suggestive diagnoses in EB were 76.5% and 23.5%, respectively. Adverse events were observed in 6 patients. In the combined group, acute obstruction of the ETV stoma was observed in 1 patient and transient double vision was observed in 1 patient. Transient aqueductal stenosis/obstruction was observed in 2 patients in the EB-alone group. In the ETV-alone group, hemorrhage was observed in 2 patients; these patients developed intratumoral hemorrhage despite ETV-alone surgery. Subsequently, these 2 patients underwent tumor removal, and the histopathological diagnosis was atypical teratoid/rhabdoid tumor in both.

CONCLUSIONS

For obstructive hydrocephalus with atypical teratoid/rhabdoid tumor, physicians must be aware of the risk of postoperative intratumoral hemorrhage after performing ETV.

A case of an atypical teratoid/rhabdoid tumor with distinctive histology in the pineal region in an adult patient

A 31‐year‐old man suffered from headaches and presented at a hospital after the symptom worsened. Obstructive hydrocephalus and a pineal tumor were identified, and he was transferred to our hospital for further investigation and treatment. Cranial computed tomography revealed a hypodense mass lesion on the right of the pineal region, and calcifications and enlargement of the lateral and third cerebral ventricles were also evident. Blood tests were negative for all tumor markers. Laparoscopic biopsy and third‐ventricle fenestration were performed that day as an emergency surgery to treat the obstructive hydrocephalus. Postoperative cranial magnetic resonance imaging revealed a solid tumor that was hypointense on T1‐weighted imaging, hyperintense on T2‐weighted imaging, and heterogeneously enhanced by Gd. Subsequently, the tumor increased in size, and craniotomy and tumorectomy were performed. Histologically, the tumor proliferated as round or short spindle‐shaped cells in a myxoid matrix, forming arrays that surrounded the blood vessels. As a few cells with eosinophilic cytoplasm were also present and immunostaining for INI‐1 was negative, the patient was diagnosed with atypical teratoid/rhabdoid tumor (AT/RT). AT/RT of the pineal region in adults is rare, and herein, we report the morphological characteristics of this case and reviewed the relevant literature.

Perinatal atypical teratoid/rhabdoid tumor involving the deep ear structures and complicated by arterial infarction

Atypical teratoid/rhabdoid tumor is a malignant pediatric brain tumor. Unusual invasive behavior of the dura and bony involvement of the deep ear structures and rapid progression in size complicated by arterial infarction have not been described before. A newborn girl presented with increased intracranial pressure. Medical imaging revealed a large mass centered in the left cerebellopontine angle and left middle cranial fossa with large supra-tentorial components associated with destruction of the left petrous bone with involvement of the inner and middle ear structures. Shortly, the tumor rapidly progressed in size and complicated by left middle cerebral artery territory infarction. The patient passed away after a short hospital course. This case report illustrates how rapid and aggressive the natural history of atypical teratoid/thabdoid tumor can be with unusual skull base destruction and deep ear structures involvement.

Fulminant presentation of a SMARCB1-deficient, anterior cranial fossa tumor in adult

Background:

Malignant atypical teratoid rhabdoid tumor (ATRT) usually develops in children. ATRTs are rare in adults, with only one case in the literature describing involvement of the anterior skull base. These primary intracranial tumors are characterized molecularly as SMARCB1 (INI1) deficient. Different types of such SMARCB1-deficient tumors exist in adulthood, usually in the form of extracranial tumors. Very few cases of such a new entity, named SMARCB1-deficient sinonasal carcinoma have been described with intracranial penetration and involvement of the anterior cranial fossa.

Case Description:

A 36-year-old male presented with acute cognitive deterioration. Over few hours, he developed a fulminant herniation syndrome. Imaging showed a tumor in the anterior cranial fossa surrounded by massive brain edema. The tumor has destroyed the frontal bone with involvement of the nasal cavities and paranasal sinuses. The patient underwent emergent decompressive craniectomy and tumor debulking but could not be saved. Pathological analysis revealed a highly cellular tumor without rhabdoid cells but with areas of necrosis. Further immunohistochemical stains revealed that neoplastic cells were diffusely and strongly positive for epithelial membrane antigen and P63 and negative for SMARCB1 (i.e., loss of expression), confirming the diagnosis of sinonasal carcinoma.

Conclusion:

To the best of our knowledge, this is the first report of a fulminant presentation of a SMARCB1- deficient tumor in young adult, involving the anterior cranial fossa and the paranasal sinuses. The main differential diagnosis of aggressive, primary, intracranial SMARCB1-deficient tumors in adults includes ATRT, SMARCB1- deficient sinonasal carcinoma, rhabdoid meningioma, and rhabdoid glioblastoma. Atypical tumors involving the anterior skull base without a clear histopathological pattern should therefore be checked for SMARCB1 expression.

Adult Pineal Region Atypical Teratoid Rhabdoid Tumor: A Case for Aggressive Surgical and Chemoradiation Management with Comprehensive Literature Review

BACKGROUND

Atypical teratoid rhabdoid tumor (ATRT) is a rare, highly malignant central nervous system neoplasm classified as an embryonal grade IV neoplasm by the World Health Organization. ATRT generally occurs in children younger than 3 years, with 85 pathologically confirmed cases reported in adults. It is most commonly supratentorial, with only 9 confirmed adult cases localized to the pineal region.

CASE DESCRIPTION

The case is described of a 29-year-old man with a history of chronic migraines and a previously negative computed tomography scan of the head presenting with worsening headaches and new-onset diplopia with upward gaze palsy. Computed tomography and magnetic resonance imaging showed a hemorrhagic pineal mass with extension into the right thalamus. After resection, the immunohistochemical staining and cytogenetic profile proved consistent with ATRT, making it the ninth reported case of pineal ATRT in an adult, which was treated aggressively with good outcome.

CONCLUSIONS

Adult ATRT is rare, especially in the pineal region, with only 9 cases reported. Because of the aggressiveness, ATRT must be considered in the differential diagnosis of pineal region lesions because early diagnosis and aggressive treatment are key to prolonged survival.

Atypical Teratoid/Rhabdoid Tumor Originated From the Trigeminal Nerve in a Young Male Adult: Case Report and Review of the Literature

Atypical teratoid/rhabdoid tumor (AT/RT) is a highly malignant central nervous system neoplasm predominantly found in children under the age of 3 years, and is extremely rare in adults. There is no specific clinical presentations or radiological features in reported cases of AT/RT. Diagnosis of brain AT/RT is mainly dependent on the classical pathological characteristics. We report a rare case of AT/RT arising from the trigeminal nerve and leading to progressively multiple cranial nerve palsies in a 25-year-old male patient. Microsurgical resection of the tumor has been performed and confirmed the diagnosis by postoperative pathology. To our knowledge, this is the second case of adult-onset AT/RT originating from the trigeminal nerve.

Spinal Atypical Rhabdoid Teratoid Tumor in an Adult Woman: Case Report and Review of the Literature

BACKGROUND

Atypical rhabdoid teratoid tumors are very rare embryonal tumors that typically affect children younger than 3 years old and are encountered intracranially.

CASE DESCRIPTION

Here, we describe the case of a 19-year-old woman who presented with gait disturbances and coccydynia. Imaging revealed a cauda equina mass. The tumor was partially resected. Histology reported loss of SMARCB1/INI1 expression and therefore the diagnosis of atypical rhabdoid teratoid was established. The patient underwent radiation treatment, but within 3 months 2 relapses were manifested.

CONCLUSIONS

Atypical rhabdoid teratoids are exceptionally rare in adults and are seldom found in spine; only 8 such cases have been reported in the medical literature. They are invariantly characterized by multiple relapses and dismal prognosis. The clinician must be attentive of leptomeningeal disseminations and 22q11 deletion-associated comorbidities.

A Systematic Review of Atypical Teratoid Rhabdoid Tumor in Adults

Background: Atypical teratoid/rhabdoid tumor in adults is a relatively rare malignant neoplasm. It is characterized by the presence of rhabdoid cells in combination with loss of either the INI1 or BRG1protein from the tumor cells.

Methods: A systematic review was conducted using MEDLINE using the terms “atypical teratoid rhabdoid tumor” AND “adult.” The systematic review was supplemented with relevant articles from the references. Cases were included if the pathology was confirmed by loss of INI1 or BRG1. We included a case from our institution. The dataset was analyzed using descriptive statistics and log-rank test.

Results: A total of 50 cases from 29 articles were included in this study. The average age at diagnosis was 36.7 years. The most common locations reported are the sellar region and cerebral hemispheres (without deep gray matter involvement). Of the 50 cases, 14 were reported to show evidence of dissemination. The average overall survival was 20 months. There was a significant difference in survival between the adjuvant therapy groups (p = < 0.0001).

Conclusion: Atypical teratoid rhabdoid tumor of the central nervous system in adults is a rare neoplasm associated with a poor prognosis in a majority of patients. The treatment and clinical course are highly variable, and it remains unclear which factors impact prognosis.

Atypical Teratoid Rhabdoid Tumor: Two Case Reports and an Analysis of Adult Cases with Implications for Pathophysiology and Treatment

We present the first quantitative analysis of atypical teratoid rhabdoid tumors (ATRT) in adults, including two patients from our own institutions. These are of interest as one occurred during pregnancy and one is a long-term survivor. Our review of pathological findings of 50 reported cases of adult ATRT leads us to propose a solely ectodermal origin for the tumor and that epithelial–mesenchymal transition (EMT) is a defining feature. Thus, the term ATRT may be misleading. Our review of clinical findings shows that ATRT tends to originate in mid-line structures adjacent to the CSF, leading to a high rate of leptomeningeal dissemination. Thus, we hypothesize that residual undifferentiated ectoderm in the circumventricular organs, particularly the pituitary and pineal glands, is the most common origin for these tumors. We note that if growth is not arrested soon after diagnosis, or after the first relapse/progression, death is almost universal. While typically rapidly fatal (as in our first case), long-term remission is possible (as in our second). Significant predictors of prognosis were the extent of resection and the use of chemotherapy. Glial differentiation (GFAP staining) was strongly associated with leptomeningeal metastases (chi-squared p = 0.02) and both predicted markedly worse outcomes. Clinical trials including adults are rare. ATRT is primarily a disease of infancy and radiotherapy is generally avoided in those aged less than 3 years old. Treatment options in adults differ from infants in that cranio-spinal irradiation is a viable adjunct to systemic chemotherapy in the adult population. Given the grave prognosis, this combined approach appears reasonable. As effective chemotherapy is likely to cause myelosuppression, we recommend that stem-cell rescue be available locally.

Primary atypical teratoid/rhabdoid tumor of the spine in an adult patient

BACKGROUND

Atypical teratoid/rhabdoid tumor (AT/RT) is an aggressive neoplasm of the central nervous system that generally arises intracranially in patients under 2 years of age. Primary spinal AT/RT in an adult is rare.

CASE DESCRIPTION

A 23-year-old female presented with left lower extremity sciatica attributed to a magnetic resonance imaging (MRI)-documented intradural mass between L2 and L4. The lesion was biopsied (was unresectable) and treated with high-dose chemotherapy (methotrexate, vincristine, cyclophosphamide, etoposide, and cisplatin) with autologous hematopoietic stem cells rescue, followed by 2 months of radiation therapy (36 Gy to craniospinal axis, 20 Gy to lumbar region) with concurrent temozolomide; the latter was discontinued after 3 weeks due to myelosuppression. Tumor relapsed 1 year later at C7-T1 level. She was started on oral metronomic therapy, and bevacizumab was added 2 months later. Three months later, a cervical MRI showed progression of the tumor, along with new lesions in the thoracic/lumbar spine plus intracranial punctate nodular tumors. Following resection of the C7/T1 lesion, she was started on palliative alisertib; a month later, a cranial computed tomography showed progression of her disease with hydrocephalus. Treatment was discontinued, and she expired 12 months after initial diagnosis.

CONCLUSION

Primary spinal AT/RT in the adult patient is rare. The pathology is associated with early recurrence and a poor prognosis. Although potential benefits of metronomic chemotherapy and alisertib have been reported, the patient in this study did not favorably respond to these modalities.

The occurrence of intracranial rhabdoid tumours in mice depends on temporal control of Smarcb1 inactivation

Rhabdoid tumours (RTs) are highly aggressive tumours of infancy, frequently localized in the central nervous system (CNS) where they are termed atypical teratoid/rhabdoid tumours (AT/RTs) and characterized by bi-allelic inactivation of the SMARCB1 tumour suppressor gene. In this study, by temporal control of tamoxifen injection in Smarcb1(flox/flox);Rosa26-Cre(ERT2) mice, we explore the phenotypes associated with Smarcb1 inactivation at different developmental stages. Injection before E6, at birth or at 2 months of age recapitulates previously described phenotypes including embryonic lethality, hepatic toxicity or development of T-cell lymphomas, respectively. Injection between E6 and E10 leads to high penetrance tumours, mainly intra-cranial, with short delays (median: 3 months). These tumours demonstrate anatomical, morphological and gene expression profiles consistent with those of human AT/RTs. Moreover, intra- and inter-species comparisons of tumours reveal that human and mouse RTs can be split into different entities that may underline the variety of RT cells of origin.

Atypical Teratoid Rhabdoid Tumor in a Teenager with Unusual Infiltration Into the Jugular Foramen

BACKGROUND

Atypical teratoid rhabdoid tumor is a rare malignant neoplasm that represents 1%-2% of all pediatric central nervous system tumors. Immunohistochemistry plays an important role in establishing the diagnosis with a loss of INI-1 staining in tumor cells. In this case report, we describe a teenager with an unusual presentation and pattern of infiltration of the tumor.

CASE DESCRIPTION

A 13-year-old boy presented with a history over several months of progressive nausea, weight loss, and hoarseness of voice associated with multiple lower cranial nerve palsies on neurologic examination. Magnetic resonance imaging revealed a large heterogeneously enhancing extra-axial neoplasm with extension and bony expansion of the jugular foramen. After near total resection, neuropathology demonstrated the absence of INI-1 expression consistent with a diagnosis of atypical teratoid rhabdoid tumor.

CONCLUSIONS

This case highlights the diverse clinical presentation and infiltrative potential of atypical teratoid rhabdoid tumors, thus expanding the differential diagnosis of extra-axial tumors invading the jugular foramen.