Atypical teratoid/rhabdoid tumor arising in a malignant glioma

SMARCB1-deficient and SMARCA4-deficient Malignant Brain Tumors With Complex Copy Number Alterations andTP53Mutations May Represent the First Clinical Manifestation of Li-Fraumeni Syndrome

Atypical teratoid/rhabdoid tumor (AT/RT) is a malignant central nervous system tumor predominantly affecting infants. Mutations ofSMARCB1or (rarely)SMARCA4causing loss of nuclear SMARCB1 or SMARCA4 protein expression are characteristic features, but further recurrent genetic alterations are lacking. Most AT/RTs occur de novo, but secondary AT/RTs arising from other central nervous system tumors have been reported. Malignant gliomas, IDH wild-type, arising in patients with Li-Fraumeni syndrome typically show somatic mutations ofTP53as well as complex copy number alterations, but little is known about the loss of SMARCB1 or SMARCA4 protein expression in this context. Here, we report 2 children in whom malignant supratentorial brain tumors with SMARCB1 deficiency, complex copy number alterations, and somaticTP53mutations lead to the discovery of pathogenic/likely pathogenicTP53variants in the germline. Screening of the molecularneuropathology.org dataset for cases with similar genetic and epigenetic alterations yielded another case with SMARCA4 deficiency in a young adult with Li-Fraumeni syndrome. In conclusion, SMARCB1-deficient or SMARCA4-deficient malignant brain tumors with complex copy number alterations and somaticTP53mutations in children and young adults may represent the first clinical manifestation of Li-Fraumeni syndrome and should prompt genetic counseling and investigation forTP53germline status.

Martial Arts-Based Therapy Reduces Pain and Distress Among Children with Chronic Health Conditions and Their Siblings

Objective

Test whether a martial arts-based therapy, Kids Kicking Cancer (KKC), can reduce pain and emotional distress in children with cancer, other chronic health conditions (e.g., sickle cell), and healthy siblings.

Methods

This study surveyed children’s pain and distress levels immediately before and after a 1-hr in-person KKC class. Eligible participants were enrolled in standard KKC classes, were diagnosed with a chronic health condition (e.g., cancer, sickle cell) or were the sibling of a child diagnosed and were between the ages of 5–17 years (inclusive). Children reported on their pain and distress using Likert-style scales (Coloured Analog Scale and modified FACES scale, respectively). Friedman test was used to test for overall changes in pain and distress, and within subgroups. Age and sex effects were evaluated using Spearman’s rank-order correlation. Additional Yes/No questions were administered regarding KKC satisfaction and use of techniques.

Results

Fifty-nine youth (19 cancer patients, 17 non-cancer patients, 23 siblings; 5–17 yrs, 26 females) completed this study. Overall, there was a significant reduction in pain (p = 0.033) and emotional distress (p < 0.001) after a 1-hr class, with 50% and 89% of youth reporting a reduction in pain and distress, respectively. On average, pain levels remained within the mild/moderate range on average (i.e., pre vs. post levels; pre: M = 1.67, post: M = 1.33) and emotional distress went from mild/moderate to none/mild distress, on average (pre: M = 1.92, post: M = 1.08). Youth with higher pre-class pain and distress reported greater reductions (p = 0.001 and p < 0.001, respectively). The reduction in pain appeared to be most pronounced with cancer and non-cancer patients. In contrast, the reduction in distress appeared to be most pronounced among healthy siblings. However, overall, reductions in pain and distress did not significantly differ among subgroups (i.e., cancer patients, non-cancer patients, siblings), and change in pain and distress was not associated with age or sex. Ninety-six percent of youth would recommend KKC to others and 81% reported using KKC techniques (e.g., the Breath Brake^TM or other martial arts techniques) outside of class, such as at home.

Conclusion

Results support the more widespread application of KKC as a psychosocial intervention for reducing pain and distress in various pediatric populations.

CNS Low-grade Diffusely Infiltrative Tumors With INI1 Deficiency, Possessing a High Propensity to Progress to Secondary INI1-deficient Rhabdoid Tumors

Atypical teratoid/rhabdoid tumors (AT/RTs) are highly malignant tumors of the central nervous system that predominantly occur in infants, and are characterized by the presence of rhabdoid cells and inactivation of INI1 or (rarely) BRG1. Most AT/RT are identified as primary tumors; however, rare AT/RT or INI1-deficient RTs arising from other primary tumors have been reported. Here, we report 3 cases of hitherto unclassifiable low-grade tumors with loss of INI1 nuclear expression, for which we propose the designation of central nervous system low-grade diffusely infiltrative tumors with INI1 deficiency (CNS LGDIT-INI1), 2 of which progressed to secondary RT. All 3 CNS LGDIT-INI1 exhibited a similar histology: diffusely distributed small tumor cells with round to oval or irregular nuclei and scant cytoplasm were admixed with degenerative neurons and large reactive astrocytes in an edematous, myxoid, or collagenous background. Mitotic figures were absent. Immunohistochemistry revealed that the tumor cells in all 3 CNS LGDIT-INI1 and 2 RT were negative for INI1. Genetically, total or partial homozygous deletions of the INI1 gene were detected in all CNS LGDIT-INI1 and RT excluding 1 CNS LGDIT-INI1 without sufficient DNA quality and quantity. Despite the loss of INI1 expression, these low-grade lesions were clearly distinguishable from AT/RT by their low proliferative activity, diffusely infiltrative growth pattern, and lack of rhabdoid cells and polyphenotypic immunoreactivity. In conclusion, CNS LGDIT-INI1 may represent a rare group of tumors that are clinically indolent but have a high propensity to progress to RT.

Secondary INI1-deficient rhabdoid tumors of the central nervous system: analysis of four cases and literature review

Atypical teratoid/rhabdoid tumors (AT/RT) are rare, highly malignant neoplasms of the central nervous system that predominantly occur in infants, and are characterized by the presence of rhabdoid cells and inactivation of INI1 or (extremely rarely) BRG1. The vast majority of AT/RT are recognized as primary tumors; however, rare AT/RT or INI1-deficient RT arising from other primary tumors have been reported. To better characterize secondary RT, we performed a histological and molecular analysis of four RT arising from pleomorphic xanthoastrocytoma (PXA), anaplastic PXA, low-grade astrocytoma, or ependymoma. Histologically, although conventional AT/RT are usually not largely composed of rhabdoid cells, three secondary RT were composed mainly of rhabdoid cells, two of which arising from (anaplastic) PXA exhibited marked nuclear pleomorphism reminiscent of that in the precursor lesions. Regarding INI1 alterations, although mutations including small indels are frequent in conventional AT/RT, only in one secondary RT had a mutation. Moreover, together with previously reported cases, biallelic INI1 inactivation in secondary RT was mostly due to biallelic focal and/or broad deletions. Although conventional AT/RT have stable chromosomal profiles, i.e., the frequency of copy number changes involving chromosomes other than chromosome 22 is remarkably low, our array comparative genomic hybridization analysis revealed numerous copy number changes in the secondary RT. In conclusion, secondary RT of the central nervous system are clinicopathologically and molecularly different from conventional pediatric AT/RT, and a nosological issue is whether these secondary RT should be called secondary "AT/RT" as most of the reported cases were.

The Rare Phenomenon of Loss of INI1 Expression at Recurrence/Progression of Primary Central Nervous System Tumors: Report of 3 Cases

It is extremely rare for loss of immunohistochemical expression of INI1 to occur primarily at recurrence/progression with retained expression at the primary/initial presentation of central nervous system (CNS) tumor. In this article, we present 3 such cases showing loss of INI1 expression primarily at recurrence. All patients were males, aged 7 years (case 1), 11 years (case 2), and 35 years (case 3), diagnosed with low-grade glial/glioneuronal tumor, not otherwise specified (case 1), craniopharyngioma (case 2), and glioblastoma (case 3); all showed retained INI1 protein expression. Case 1 at 12 months recurrence showed a high-grade tumor with relative undifferentiated morphology, case 2 after 104 months showed a sarcomatous progression, and case 3 recurred after 4 months with the presence of relative undifferentiated round cells. All these recurrences showed loss of INI1 expression. Loss of SMARCB1/INI1 gene function resulting in complete loss of INI1 protein expression is not a well-accepted genetic mechanism for transformation/progression as this series emphasizes.

A Pediatric Intra-Axial Malignant SMARCB1-Deficient Desmoplastic Tumor Arising in Meningioangiomatosis

SMARCB1 inactivation is a well-established trigger event in atypical teratoid/rhabdoid tumor. Recently, a role for SMARCB1 inactivation has emerged as a mechanism of clonal evolution in other tumor types, including rare brain tumors. We describe an unusual malignant intra-axial SMARCB1-deficient spindle cell desmoplastic neoplasm, occurring in a 6-year-old child with meningioangiomatosis and a long history of seizures. Striking features of the tumor were a storiform pattern and strong CD34 expression. Undifferentiated round cell areas with isolated rhabdoid cells showing high mitotic index and focal necrosis with INI1 expression loss were present. The meningioangiomatosis component showed few chromosomal imbalances, including chromosomal 22 monosomy (where SMARCB1 maps) and gain at 6q14.3. In addition to these abnormalities, the spindle cell desmoplastic neoplasm and its dedifferentiated SMARCB1-deficient component shared several other aberrations, including homozygous deletion at 9p21.3, losses at 1p, 3p, 3q, 10p, and 13q, gains and losses at 5p and 11p. In line with INI1 loss, the dedifferentiated component showed remarkably decreased levels of SMARCB1 transcript. The residual SMARCB1 allele was wildtype. Our findings suggest progression from the meningioangiomatosis to the malignant desmoplastic neoplasm through the occurrence of complex chromosomal abnormalities, and point to functional silencing of SMARCB1 in the dedifferentiation component.

Hereditary SWI/SNF complex deficiency syndromes

The SWItch Sucrose non-fermentable (SWI/SNF) complex is a highly conserved multi-subunit complex of proteins encoded by numerous genes mapped to different chromosomal regions. The complex regulates the process of chromatin remodelling and hence plays a central role in the epigenetic regulation of gene expression, cell proliferation and differentiation. During the last three decades, the SWI/SNF complex has been increasingly recognized as a central molecular event driving the initiation and/or progression of several benign and malignant neoplasms of different anatomic origin and having diverse histomorphological appearance. Atypical teratoid/rhabdoid tumors (AT/RT) and renal/extrarenal malignant rhabdoid tumors of childhood, epithelioid sarcoma and small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) represent the most commonly recognized SWI/SNF-driven neoplasms. Approximately one-third of pediatric malignant rhabdoid tumors are linked to germline SWI/SNF alterations (SMARCB1/INI1, rarely SMARCA4) resulting in occasional familial clustering of these highly aggressive malignancies (so-called rhabdoid tumor predisposition syndrome, RTPS, types 1 and 2, respectively). However, more recently, inherited SWI/SNF-deficiency has been linked to several benign syndromic tumors including a subset of familial schwannomatosis (linked to SMARCB1) and multiple meningiomas (linked to SMARCE1) as well as others. Beyond neoplasms, several congenital developmental functional disorders such as Coffin-Siris syndrome and intellectual disability are now known to be SWI/SNF-related. The latter are essentially not associated with SWI/SNF-driven neoplasms, although at least anecdotal cases have documented concurrence of both neoplastic and developmental disorders. This review summarizes the most important SWI/SNF-driven diseases with a main focus on neoplasms.