Optical genome mapping identifies a germline retrotransposon insertion in SMARCB1 in two siblings with atypical teratoid rhabdoid tumors.

In a subset of pediatric cancers, a germline cancer predisposition is highly suspected based on clinical and pathological findings, but genetic evidence is lacking, which hampers genetic counseling and predictive testing in the families involved. We describe a family with two siblings born from healthy parents who were both neonatally diagnosed with atypical teratoid rhabdoid tumor (ATRT). This rare and aggressive pediatric tumor is associated with biallelic inactivation of SMARCB1, and in 30% of the cases, a predisposing germline mutation is involved. Whereas the tumors of both siblings showed loss of expression of SMARCB1 and acquired homozygosity of the locus, whole exome and whole genome sequencing failed to identify germline or somatic SMARCB1 pathogenic mutations. We therefore hypothesized that the insertion of a pathogenic repeat-rich structure might hamper its detection, and we performed optical genome mapping (OGM) as an alternative strategy to identify structural variation in this locus. Using this approach, an insertion of ~2.8 kb within intron 2 of SMARCB1 was detected. Long-range PCR covering this region remained unsuccessful, but PacBio HiFi genome sequencing identified this insertion to be a SINE-VNTR-Alu, subfamily E (SVA-E) retrotransposon element, which was present in a mosaic state in the mother. This SVA-E insertion disrupts correct splicing of the gene, resulting in loss of a functional allele. This case demonstrates the power of OGM and long-read sequencing to identify genomic variations in high-risk cancer-predisposing genes that are refractory to detection with standard techniques, thereby completing the clinical and molecular diagnosis of such complex cases and greatly improving counseling and surveillance of the families involved. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Multimodal Management of Congenital Orbital Malignant Rhabdoid Tumor: Review of Literature and Report of a Rare Case.

BACKGROUND: Malignant rhabdoid tumor (MRT) is a rare and aggressive tumor with a dismal prognosis. It commonly arises in the brain (65%), soft tissues (26%), and the kidney (9%). Primary orbital involvement is extremely rare. Although it has been mostly described in children below 2 years old, presentation at birth is sparsely reported. OBSERVATION: We have described a case of congenital orbital MRT, who presented with rapidly progressive right-sided proptosis and was initially treated with subtotal resection and postoperative chemotherapy with ICE (Ifosfamide, Carboplatin, Etoposide) regimen. On local progression the child was treated with palliative radiotherapy (20 Gy) to the right orbit and second-line chemotherapy with VAC (Vincristine, Adriamycin, Cyclophosphamide) regimen. Unfortunately he died due to progressive disease 4 months after the initial diagnosis. CONCLUSIONS: This report highlights the importance of awareness of orbital MRT as a differential diagnosis of rapidly progressing proptosis in the neonatal period. This tumor is often refractory to conventional multimodality treatment and more intensive and innovative treatment approaches are clearly needed in future.

Spontaneous Regression of Atypical Teratoid Rhabdoid Tumor Without Therapy in a Patient With Uncommon Regional Inactivation of SMARCB1 ( hSNF5/INI1).

Atypical teratoid/rhabdoid tumor (ATRT) is a high-grade central nervous system tumor, with poor prognosis despite intensive multimodal therapy. Loss of nuclear immunostaining for INI1 due to inactivation of the hSNF5/INI1 tumor suppressor gene is pathognomonic of ATRT. We present a patient with congenital ATRT, who had spontaneous tumor regression without therapy, and is disease-free 4 years later. Tumor histopathology showed rhabdoid cells characteristic of ATRT, but immunohistochemistry revealed heterogeneous loss of nuclear INI1 staining. The populations of INI1-intact and INI1-deficient cells were separated by laser microdissection, for molecular analysis with DNA sequencing and fluorescence in situ hybridization. The INI1-negative cells were found to harbor a heterozygous deletion and truncating mutation of the hSNF5/INI1 locus, while the INI1-intact cells had 2 copies of the wild-type INI1 gene. To our knowledge, this is the first report of spontaneous regression of ATRT, with molecular heterogeneity for SMARCB1 inactivation, with no radiographic signs of recurrence at 4 years after diagnosis.

Tumour lysis in newborn: spontaneous or secondary to antenatal steroids?

Malignancies are rare in the early neonatal period. Common congenital tumours include malignant teratoma and neuroblastomas. Tumour lysis syndrome is a serious condition usually seen after commencement of chemotherapy for a malignancy. Rare case reports of spontaneous tumour lysis have been reported though not in the newborn period. We report here an instance of tumour lysis syndrome in a newborn with congenital rhabdoid tumour, where the cause was either spontaneous or related to antenatal steroid exposure.

The extraordinary challenge of treating patients with congenital rhabdoid tumors-a collaborative European effort.

BACKGROUND: Congenital rhabdoid tumors are rare and highly aggressive malignancies. In general, patients are considered to be incurable and are often treated using an exclusive, primarily palliative approach. METHODS: A prospective and retrospective collection of 42 patients from the European Rhabdoid Registry (EU-RHAB), France and Moscow (2006-2016) diagnosed within the first 28 days of life was evaluated. Genetic and clinical reference evaluation included SMARCB1 and/or SMARCA4 (fluorescence-in-situ-hybridization, multiplex ligation-dependent probe amplification, and sequencing) mutation analysis and immunohistochemistry. Forty-eight percent (20/42) of patients were treated according to the EU-RHAB therapy, 7% (3/42) according to the pilot approach Rhabdoid 2007, 33% (14/42) with individual schedules, and 12% (5/42) received no chemotherapy at all. RESULTS: Forty point five percent (17/42) of patients presented with extracranial rhabdoid tumors, 33.5% (14/42) with rhabdoid tumors of the central nervous system (atypical teratoid/rhabdoid tumor), and the remainder 26% (11/42) demonstrated synchronous tumors. Metastases at diagnosis were present in 52% (22/42) of patients. A germline mutation was detected in 66% (25/38) and was associated with a poor prognosis (4.2 ± 4.1% vs. 48 ± 16.4%, P < 0.00005). A gross total resection (GTR) was realized in 17%. A GTR (42.9 ± 18.7% vs. 4.9 ± 4.3%, P = 0.04), therapy according to a standardized approach (20.9 ± 8.7% vs. 7.1 ± 6.9 %, P = 0.0018), and a complete remission (CR) (23.6 ± 9.8% vs. 1.3 ± 3.6%, P = 0.04) were significant prognostic factors. CONCLUSIONS: The management of patients with congenital rhabdoid tumors requires a major multidisciplinary effort. In many instances, cure is not possible and a palliative approach is warranted. Our data indicate a positive impact of standardized therapeutic approaches on survival, making a tailored approach toward affected patients and their families mandatory.

Disseminated Malignant Rhabdoid Tumor of the Head and Neck.

Disseminated extrarenal malignant rhabdoid tumors of the head and neck are very rare, but aggressive tumors. Although the features on radiological imaging may be nonspecific, the imaging is useful for assessing the extent of tumor involvement. Key pathologic features are those of a cellular "blue cell tumor" with variable rhabdoid appearance. These cells express a combination of markers usually viewed as characteristic of diverse lines of differentiation, including EMA, cytokeratins, smooth muscle markers, and GFAP, and occasionally synaptophysin. At a molecular level, the entity is defined by mutations or alterations in the SMARB1/INI1 gene resulting in loss of INI1 expression. Diagnostic features include rhabdoid cells, expression of keratin with absence of desmin, S100 protein and CD34, and loss of INI1 expression. These features are exemplified in this sine qua non radiology-pathology correlation article.

Ultra early recurrence in giant congenital malignant rhabdoid tumor of spine.

BACKGROUND: Malignant rhabdoid tumor (MRT) is an aggressive tumor of infancy and childhood that rarely presents as a primary spinal or spinal cord tumor. There are only three reported cases of spinal MRT in infants. OBJECTIVE: We present a similar case in a 3-month male child who developed ultra-early recurrence, 4 weeks after complete excision. The diagnosis was confirmed by immunohistochemistry showing inactivation of the INI1 gene. RESULT: Despite surgical excision and adjuvant chemoradiotherapy, these tumors have a progressive course and recurrence is a common phenomenon. CONCLUSION: We believe that MRT must be considered in the differential diagnosis of the intra/paraspinal masses, especially in the infants.

Congenital Disseminated Extrarenal Malignant Rhabdoid Tumor.

Soft tissue tumors arising in association with genetic or malformation syndromes have been increasingly reported. Malignant rhabdoid tumor (MRT) is a highly aggressive neoplasm of infancy and young childhood, characterized by typical morphology and biallelic inactivation of the SMARCB1 (INI1/hSNF5/BAF47) gene on chromosome 22q.2 which encodes a subunit of the SWI/SNF ATP-dependent chromatin remodeling complex. Congenital infantile disseminated MRT represents a unique clinicopathologic presentation of this tumor. We report a case occurring in a female neonate who presented at birth a voluminous left thigh mass. Surgical biopsy performed at day 9 showed morphology and immunoprofile of MRT. Staging evaluation identified hypercalcemia and distant nodules. The mass showed rapid growth. Despite chemotherapy, the tumor progressed with exteriorization through the biopsy scar. Chemotherapy was discontinued and treatment limited to palliative care and the child died on day 51. The tumor was homozygous for the SMARCB1 deletion with apparent de novo heterozygous germ line deletion in the infant, not identified in the parents.

Congenital multifocal rhabdoid tumor: a case with peculiar biological behavior and different response to treatment according to location (central nervous system and kidney).

Atypical teratoid/rhabdoid tumor (AT/RT) of the central nervous system and malignant rhabdoid tumor of the kidney (MRTK) may present with different responses to chemotherapy and outcomes. We describe the case of an infant with multifocal rhabdoid tumor with different behavior and response to treatment, depending on the anatomic site.

Synchronous congenital malignant rhabdoid tumor of the orbit and atypical teratoid/rhabdoid tumor--feasibility and efficacy of multimodal therapy in a long-term survivor.

Among infant malignancies, congenital tumors, especially those of the central nervous system (CNS), constitute a rather unique subgroup. Poor survival rates (28% in CNS tumors) may be attributed to the aggressive biology as well as specific therapeutic limitations innate to the young age of affected patients. Our patient developed synchronous congenital tumors: an atypical teratoid/rhabdoid tumor (AT/RT) localized in the right lateral ventricle of the brain and a malignant rhabdoid tumor (MRT) in the soft tissue of the right orbit. A de novo germline chromosomal deletion in 22q encompassing the SMARCB1 gene was detected, prompting the diagnosis of a de novo rhabdoid tumor predisposition syndrome 1 (RTPS1). The patient was reported to the European Rhabdoid Registry (EU-RHAB) and treated according to the Rhabdoid 2007 recommendation. Despite the very young age of the patient, the initially desperate situation of RTPS1, and the synchronous localization of congenital rhabdoid tumors, intensive chemotherapy was well tolerated; the child is still in complete remission 5 years following diagnosis. In conclusion, RTPS1 with congenital synchronous MRTs is not necessarily associated with a detrimental outcome. Intensive multidrug chemotherapy, including high dose chemotherapy, may be feasible and justified.

Congenital extrarenal malignant rhabdoid tumor in an infant with distal 22q11.2 deletion syndrome: the importance of SMARCB1.

Extrarenal rhabdoid tumor is a rare malignancy of infants and children, typically presenting in the soft tissue of deep, axial locations. We describe a rare dermal presentation of congenital extrarenal rhabdoid tumor in the left paraspinal region of a 6-month-old girl with germline deletion of chromosome 22q11.21q11.23. This case demonstrates that like other rhabdoid tumors, the SMARCB1 gene is also responsible for cutaneous extrarenal rhabdoid tumor oncogenesis.

Congenital malignant rhabdoid tumor of the scalp.

BACKGROUND: Malignant rhabdoid tumors (MRT) are rare but aggressive tumors presenting in the pediatric population. First thought a variant of Wilms' tumor in the kidney, it is recognized as presenting at renal, central nervous system and other extra-renal primary sites. It is uniformly of very poor prognosis, however. CASE REPORT AND DISCUSSION: We present a case of congenital MRT of the scalp, which we believe to be the first described at this site. The clinical and histopathological features of the tumor are discussed in light of the current literature on MRT at other sites. The bleak prognosis at this site appears to be no different from others - the child succumbed at 10 months old despite surgical resection and initial excellent response to chemotherapy. CONCLUSION: Malignant rhabdoid tumor has a very poor prognosis and needs to be considered in the differential diagnosis of similar lesions by clinicians involved in pediatric head and neck care.

Fetal and neonatal rhabdoid tumor.

PURPOSE: Few studies have focused on the behavior of rhabdoid tumor (RT) in the fetus and neonate. The purpose of this review is to show that perinatal RTs are associated with unusual findings and a poor prognosis. METHODS: The author conducted a 40-year systematic review of the literature. Clinical presentation, pathology, management, and outcome of 72 fetuses and neonates with RTs are discussed. RESULTS: Seventy-two fetuses and neonates presented with RTs detected prenatally (n = 12) and during the neonatal period (n = 60). The review consisted of 3 main groups: extrarenal noncentral nervous system (CNS) RT, renal RT, and CNS RT. There were some group differences in survival: extrarenal non-CNS RT (3/33 or 9.1%), renal RT (2/27 or 7.4%), and CNS RT (2/12 or 16.7%). Metastatic RT was present at diagnosis in more than half the patients (41/72 or 57%) who had a survival of 2.3%. The overall survival was 9.7%. For statistical results, there was no significant difference in survival among the 3 groups by type of tumor (P = .692). chi(2) analysis for survival with and without metastases was not valid due to small sample size. CONCLUSIONS: The review shows that extrarenal RT was more common than either renal RT or CNS RT groups that is different than that observed in older individuals. Concomitant brain tumors were found in almost a third of fetuses and neonates. The CNS involvement occurred more often in patients with renal RT than in those with extrarenal RT. Metastatic disease at diagnosis was noted in more than half of the patients. Higher stage and presence of a CNS tumor were significant determinants in survival.

Congenital tumors of the central nervous system: the MCH experience.

INTRODUCTION: Congenital brain tumors in the younger pediatric population are rare lesions that are histologically distinct from those in the older pediatric population. Malignant histology is common, with persistently poor outcomes despite accessible neuroimaging and evolving adjuvant therapy. There remains scant literature about the natural history of these patients because of rarity and varied institutional experiences. METHODS: A retrospective review was performed of congenital brain tumor patients surgically treated at the Montreal Children's Hospital (MCH) over a 22-year period. Patients presenting in the first year of life were evaluated for demographic information, presenting symptoms, lesion location, and management. Analysis was by median rank test and chi(2) statistics. RESULTS: 13 cases of congenital brain tumors were identified: 5 supratentorial and 8 infratentorial. Median age (p = 0.93) and gender (p = 0.57) did not differ by location, and predominant histologies were choroid plexus papilloma and primitive neuroectodermal tumor. Seizure activity was exclusive to supratentorial lesions (40%, p = 0.03), with hypotonia observed only among infratentorial lesions (50%, p = 0.02). There was equal incidence of hydrocephalus (69%, p = 0.57) and increasing head circumference (38%, p = 0.27) by lesion location. Supratentorial lesions were treated by total resection (n = 3), subtotal resection (n = 1), and biopsy (n = 1). Infratentorial lesions were treated by total resection (n = 1), subtotal resection (n = 2), biopsy (n = 1), no operation (n = 2), and decompressive laminectomy for two spinal lesions. CONCLUSIONS: Congenital brain tumor patients represent fewer than 2% of patients treated at MCH. An evolving understanding of management objectives for these lesions requires understanding institutional experiences. Patients with supratentorial lesions frequently present with seizures, hydrocephalus, and macrocrania, and more frequently underwent total resection at surgery.

Childhood atypical teratoid rhabdoid tumor of the central nervous system: a meta-analysis of observational studies.

PURPOSE: Therapy for central nervous system (CNS) atypical teratoid rhabdoid tumor (ATRT) is controversial. We describe 4 children treated with sarcoma-like therapy and review the literature to evaluate outcome in relation to treatment modalities. PROCEDURE: Reports from 1995 to 2007, describing clinical features of children (< or =18 years) were reviewed for details of demography, therapy, and outcome. Kaplan-Meier survival analyses were used to study the impact of clinical features, demography, and therapy on overall survival (OS). RESULTS: The median OS for patients treated with multiagent chemotherapy (n=79) was 17.3 months (range, 1.5-93 mo); unrelated to age at diagnosis, sex, tumor site, and extent of resection. Overall mortality was 67%. Disease progression (craniospinal spread in 58%) was the major cause of death. Patients (n=30) treated with intrathecal (IT) chemotherapy had significantly higher 2-year OS [64% (95% confidence interval, 46.5-82.0) vs. 17.3% (95% confidence interval, 5.4-29.3); P<0.0001] and lower prevalence of distant CNS metastasis compared with those without IT therapy (n=49) (20% vs. 59.2%; P=0.001). CONCLUSIONS: Despite dismal OS, multimodal therapy can induce remission even in metastatic CNS ATRT with partial resection. IT chemotherapy results in higher OS and, because of an overall high rate of distant relapse, should be considered in future trials.

A case of congenital orbital malignant rhabdoid tumor: systemic metastasis following exenteration.

A newborn girl presented with massive proptosis of the right eye. Physical and radiologic examination disclosed that the primary orbital mass was confined to the site. A diagnosis of malignant rhabdoid tumor was made by histopathologic examination of an incisional biopsy specimen. Exenteration was performed, and the resection margins were free from tumor cells. However, distant metastasis developed in the liver 1 month after surgery. Despite chemotherapy, the patient died 2 months later due to tumor invasion into the central nervous system, which was confirmed by autopsy. To the best of our knowledge, this is the first case of congenital orbital malignant rhabdoid tumor showing systemic metastasis after exenteration, which suggests the need for aggressive systemic treatment rather than exenteration, even in a case of locally confined tumor.

A case of congenital supratentorial tumor: atypical teratoid/rhabdoid tumor or primitive neuroectodermal tumor?

Two embryonal CNS tumors, atypical teratoid/rabdoid tumor (AT/RT) and primitive neuroectodermal tumor (PNET), may be confused with each other and misdiagnosed. Here we report an infant with a congenital supratentorial tumor, which was detected by fetal MRI at 37 weeks gestation. On routine histological examination, the tumor was composed mainly of small undifferentiated cells, among which many rhabdoid cells and occasional sickle-shaped embracing cells were observed. No mesenchymal or epithelial areas were evident. Our impression was that the tumor was an atypical example of AT/RT. Immunohistochemically, almost all the tumor cells were strongly positive for vimentin. However, epithelial membrane antigen was notably negative, and most of the tumor cell nuclei were clearly positive for INI1. In addition, many tumor cells were positive for neurofilament protein. There were also occasional small areas containing many tumor cells positive for glial fibrillary acidic protein. Finally, a diagnosis of PNET, with a rhabdoid phenotype and expression of neuronal and glial markers, was made. In the present case, application of INI1 immunostaining was very helpful for distinguishing PNET from AT/RT.

Congenital cerebellar malignant rhabdoid tumor in an infant with junctional epidermolysis bullosa.

Epidermolysis bullosa (EB), a hereditary blistering condition of the skin, is divided into simplex, hemidesmosomal, junctional, and dystrophic types. It may be complicated by the development of squamous cell carcinoma of the skin, but other neoplasms, especially those separate from involved skin, are distinctly rare. We report a male infant with junctional EB who died of Pseudomonas sepsis and was found at autopsy to have a clinically unrecognized cerebellar malignant rhabdoid tumor (MRT). This is the first reported case of an infant with EB and a coincident extracutaneous neoplasm. It is also the first known case of EB associated with a pathologically confirmed malignant brain tumor. Cytogenetic results from the infant and his tumor and both of his parents suggest the infant's EB and MRT were not genetically linked.