Spectrum of SMARCB1/INI1 mutations in familial and sporadic rhabdoid tumors

BACKGROUND

Germline mutations and deletions of SMARCB1/INI1 in chromosome band 22q11.2 predispose patients to rhabdoid tumor and schwannomatosis. Previous estimates suggested that 15-20% of rhabdoid tumors were caused by an underlying germline abnormality of SMARCB1. However, these studies were limited by case selection and an inability to detect intragenic deletions and duplications.

PROCEDURE

One hundred matched tumor and blood samples from patients with rhabdoid tumors of the brain, kidney, or soft tissues were analyzed for mutations and deletions of SMARCB1 by FISH, multiplex ligation-dependent probe amplification (MLPA), sequence analysis and high resolution Illumina 610K SNP-based oligonucleotide array studies.

RESULTS

Thirty-five of 100 patients were found to have a germline SMARCB1 abnormality. These abnormalities included point and frameshift mutations, intragenic deletions and duplications, and larger deletions including regions both proximal and distal to SMARCB1. There were nine cases that demonstrated parent to child transmission of a mutated copy of SMARCB1. In eight of the nine cases, one or more family members were also diagnosed with rhabdoid tumor or schwannoma, and two of the eight families presented with multiple affected children in a manner consistent with gonadal mosaicism.

CONCLUSIONS

Approximately one-third of newly diagnosed patients with rhabdoid tumor have an underlying genetic predisposition to tumors due to a germline SMARCB1 alteration. Families may demonstrate incomplete penetrance and gonadal mosaicism, which must be considered when counseling families of patients with rhabdoid tumor.

BAF250B-associated SWI/SNF chromatin-remodeling complex is required to maintain undifferentiated mouse embryonic stem cells

Whether SWI/SNF chromatin remodeling complexes play roles in embryonic stem (ES) cells remains unknown. Here we show that SWI/SNF complexes are present in mouse ES cells, and their composition is dynamically regulated upon induction of ES cell differentiation. For example, the SWI/SNF purified from undifferentiated ES cells contains a high level of BAF155 and a low level of BAF170 (both of which are homologs of yeast SWI3 protein), whereas that from differentiated cells contains nearly equal amounts of both. Moreover, the levels of BAF250A and BAF250B decrease during the differentiation of ES cells, whereas that of BRM increases. The altered expression of SWI/SNF components hinted that these complexes could play roles in ES cell maintenance or differentiation. We therefore generated ES cells with biallelic inactivation of BAF250B and found that these cells display a reduced proliferation rate and an abnormal cell cycle. Importantly, these cells are deficient in the self-renewal capacity of undifferentiated ES cells and exhibit certain phenotypes of differentiated cells, including reduced expression of several pluripotency-related genes and increased expression of some differentiation-related genes. These data suggest that the BAF250B-associated SWI/SNF is essential for mouse ES cells to maintain their normal proliferation and pluripotency. The work presented here underscores the importance of SWI/SNF chromatin remodeling complexes in pluripotent stem cells.

Loss of switch/sucrose non-fermenting complex protein expression is associated with dedifferentiation in endometrial carcinomas

Dedifferentiated endometrial carcinoma is an aggressive type of endometrial cancer that contains a mix of low-grade endometrioid and undifferentiated carcinoma components. We performed targeted sequencing of eight dedifferentiated carcinomas and identified somatic frameshift/nonsense mutations in SMARCA4, a core ATPase of the switch/sucrose non-fermenting (SWI/SNF) complex, in the undifferentiated components of four tumors. Immunohistochemical analysis confirmed the loss of SMARCA4 in the undifferentiated component of these four SMARCA4-mutated cases, whereas the corresponding low-grade endometrioid component showed retained SMARCA4 expression. An expanded survey of other members of the SWI/SNF complex showed SMARCB1 loss in the undifferentiated component of two SMARCA4-intact tumors, and all SMARCA4- or SMARCB1-deficient tumors showed concomitant loss of expression of SMARCA2. We subsequently examined the expression of SMARCA2, SMARCA4, and SMARCB1 in an additional set of 22 centrally reviewed dedifferentiated carcinomas and 31 grade 3 endometrioid carcinomas. Combining the results from the index and the expansion set, 15 of 30 (50%) of the dedifferentiated carcinomas examined showed either concurrent SMARCA4 and SMARCA2 loss (37%) or concurrent SMARCB1 and SMARCA2 loss (13%) in the undifferentiated component. The loss of SMARCA4 or SMARCB1 was mutually exclusive. All 31 grade 3 endometrioid carcinomas showed intact expression of these core SWI/SNF proteins. The majority (73%) of the SMARCA4/SMARCA2-deficient and half of SMARCB1/SMARCA2-deficient undifferentiated component developed in a mismatch repair-deficient molecular context. The observed spatial association between SWI/SNF protein loss and histologic dedifferentiation suggests that inactivation of these core SWI/SNF proteins may contribute to the development of dedifferentiated endometrial carcinoma.

INI1 mutations in meningiomas at a potential hotspot in exon 9

Rhabdoid tumours have been shown to carry somatic mutations in the INI1 (SMARCB1/hSNF5) gene. A considerable fraction of these tumours exhibit allelic losses on chromosome 22. Allelic loss on 22q also is characteristic for meningiomas, however most of these alterations are considered to be associated with mutations of the NF2 gene. We examined a series of 126 meningiomas for alterations in the INI1 gene. Four identical somatic mutations in exon 9 were detected resulting in an exchange of Arg to His in position 377 of INI1. Our observations were reproduced both by using DNA from a new round of extraction and by employing overlapping primers. This mutational hotspot therefore appears to be an important target in the formation of a fraction of meningiomas. In addition, 4 novel polymorphisms of INI1 were characterized. Our data indicate that the INI1 is a second tumour suppressor gene on chromosome 22 that may be important for the genesis of meningiomas.

Rhabdoid tumor: gene expression clues to pathogenesis and potential therapeutic targets

Rhabdoid tumors (RT) are aggressive tumors characterized by genetic loss of SMARCB1 (SNF5, INI-1), a component of the SWI/SNF chromatin remodeling complex. No effective treatment is currently available. This study seeks to shed light on the SMARCB1-mediated pathogenesis of RT and to discover potential therapeutic targets. Global gene expression of 10 RT was compared with 12 cellular mesoblastic nephromas, 16 clear cell sarcomas of the kidney, and 15 Wilms tumors. In all, 114 top genes were differentially expressed in RT (P<0.001, fold change >2 or <0.5). Among these were downregulation of SMARCB1 and genes previously associated with SMARCB1 (ATP1B1, PTN, DOCK4, NQO1, PLOD1, PTP4A2, PTPRK); 28/114 top differentially expressed genes were involved with neural or neural crest development and were all sharply downregulated. This was confirmed by Gene Set Enrichment Analysis (GSEA). Neural and neural crest stem cell marker proteins SOX10, ID3, CD133, and Musashi were negative by immunohistochemistry, whereas Nestin was positive. Decreased expression of CDKN1A, CDKN1B, CDKN1C, CDKN2A, and CCND1 was identified, while MYC-C was upregulated. GSEA of independent gene sets associated with bivalent histone modification and polycomb group targets in embryonic stem cells showed significant negative enrichment in RT. Several differentially expressed genes were associated with tumor suppression, invasion, and metastasis, including SPP1 (osteopontin), COL18A1 (endostatin), PTPRK, and DOCK4. We conclude that RTs arise within early progenitor cells during a critical developmental window in which loss of SMARCB1 directly results in repression of neural development, loss of cyclin-dependent kinase inhibition, and trithorax/polycomb dysregulation.

Pediatric rhabdoid tumors of kidney and brain show many differences in gene expression but share dysregulation of cell cycle and epigenetic effector genes

BACKGROUND

Rhabdoid tumors (RTs) are aggressive tumors of early childhood that occur most often in brain (AT/RTs) or kidney (KRTs). Regardless of location, they are characterized by loss of functional SMARCB1 protein, a component of the SWI/SNF chromatin remodeling complex. The aim of this study was to determine genes and biological process dysregulated in common to both AT/RTs and KRTs.

PROCEDURE

Gene expression for AT/RTs was compared to that of other brain tumors and normal brain using microarray data from our lab. Similar analysis was performed for KRTs and other kidney tumors and normal kidney using data from GEO. Dysregulated genes common to both analyses were analyzed for functional significance.

RESULTS

Unsupervised hierarchical clustering of RTs identified three major subsets: two comprised of AT/RTs, and one of KRTs. Compared to other tumors, 1,187, 663, and 539 genes were dysregulated in each subset, respectively. Only 14 dysregulated genes were common to all three subsets. Compared to normal tissue, 5,209, 4,275, and 2,841 genes were dysregulated in each subset, with an overlap of 610 dysregulated genes. Among these genes, processes associated with cell proliferation, MYC activation, and epigenetic dysregulation were common to all three RT subsets.

CONCLUSIONS

The low overlap of dysregulated genes in AT/RTs and KRTs suggests that factors in addition to SMARCB1 loss play a role in determining subsequent gene expression. Drugs which target cell cycle or epigenetic genes may be useful in all RTs. Additionally, targeted therapies tailored to specific RT subset molecular profiles should be considered.

Pain correlates with germline mutation in schwannomatosis

Schwannomatosis has been linked to germline mutations in the SMARCB1 and LZTR1 genes, and is frequently associated with pain.In a cohort study, we assessed the mutation status of 37 patients with clinically diagnosed schwannomatosis and compared to clinical data, whole body MRI (WBMRI), visual analog pain scale, and Short Form 36 (SF-36) bodily pain subscale.We identified a germline mutation in LZTR1 in 5 patients (13.5%) and SMARCB1 in 15 patients (40.5%), but found no germline mutation in 17 patients (45.9%). Peripheral schwannomas were detected in 3 LZTR1-mutant (60%) and 10 SMARCB1-mutant subjects (66.7%). Among those with peripheral tumors, the median tumor number was 4 in the LZTR1 group (median total body tumor volume 30 cc) and 10 in the SMARCB1 group (median volume 85cc), (P=.2915 for tumor number and P = .2289 for volume). mutation was associated with an increased prevalence of spinal schwannomas (100% vs 41%, P = .0197). The median pain score was 3.9/10 in the LZTR1 group and 0.5/10 in the SMARCB1 group (P = .0414), and SF-36 pain-associated quality of life was significantly worse in the LZTR1 group (P = .0106). Pain scores correlated with total body tumor volume (rho = 0.32471, P = .0499), but not with number of tumors (rho = 0.23065, P = .1696).We found no significant difference in quantitative tumor burden between mutational groups, but spinal schwannomas were more common in LZTR1-mutant patients. Pain was significantly higher in LZTR1-mutant than in SMARCB1-mutant patients, though spinal tumor location did not significantly correlate with pain. This suggests a possible genetic association with schwannomatosis-associated pain.

Therapeutic Targeting of EZH2 and BET BRD4 in Pediatric Rhabdoid Tumors

Aberrant activity of the H3K27 modifiers EZH2 and BRD4 is an important oncogenic driver for atypical teratoid/rhabdoid tumor (AT/RT), and each is potentially a possible therapeutic target for treating AT/RT. We, therefore, determined whether targeting distinct histone modifier activities was an effective approach for treating AT/RT. The effects of EZH2 and BRD4 inhibition on histone modification, cell proliferation, and cell invasion were analyzed by immunoblotting, MTS assay, colony formation assay, and cell invasion assay. RNA- and chromatin immunoprecipitation-sequencing were used to determine transcriptional and epigenetic changes in AT/RT cells treated with EZH2 and BRD4 inhibitors. We treated mice bearing human AT/RT xenografts with EZH2 and BRD4 inhibitors. Intracranial tumor growth was monitored by bioluminescence imaging, and the therapeutic response was evaluated by animal survival. AT/RT cells showed elevated levels of H3K27 trimethylation (H3K27me3) and H3K27 acetylation (H3K27ac), with expression of EZH2 and BRD4, and lack of SMARCB1 proteins. Targeted inhibition of EZH2 and BRD4 activities reduced cell proliferation and invasiveness of AT/RT in association with decreasing H3K27me3 and H3K27ac. Differential genomic occupancy of H3K27me3 and H3K27ac regulated specific gene expression in response to EZH2 and BRD4 inhibitions. A combination of EZH2 and BRD4 inhibition increased the therapeutic benefit in vitro and in vivo, outperforming either monotherapy. Overall, histones H3K27me3 and H3K27ac were elevated in AT/RT cells and distributed in distinct chromatin regions to regulate specific gene expression and to promote AT/RT growth. Targeting EZH2 and BRD4 activity is, therefore, a potential combination therapy for AT/RT.

Molecular hallmarks of renal medullary carcinoma: more to c-MYC than meets the eye

Renal medullary carcinoma (RMC) is a lethal disease that predominantly afflicts young individuals with sickle cell trait. Our recently reported molecular profiling of primary untreated RMC tissues elucidated distinct genomic and immune hallmarks of RMC, and identified MYC-induced replication stress as a targetable vulnerability for this disease.

Malignant peripheral nerve sheath tumor of the trigeminal nerve: clinicopathologic features in a young adult patient

Malignant peripheral nerve sheath tumors (MPNSTs) arising from cranial nerves are rare and usually affect adults. Here we report the clinicopathologic features of a young adult patient with a trigeminal nerve MPNST, in whom another tumor involving the oculomotor nerve on the contralateral side was evident. The patient, an 18-year-old woman, had suffered recurrent paroxysmal sharp stabbing pain over her cheek and forehead on the right side for 1 month. A brain MRI study disclosed a mass, 35 mm in diameter, in the right Meckel's cave, and another mass, 10 mm in diameter, involving the intracranial portion of the left oculomotor nerve. Following gadolinium administration, the former and latter tumors exhibited strong and weak enhancement, respectively. The patient had no clinical stigmata characteristic of neurofibromatosis type 1. Following a tentative diagnosis of schwannoma, total resection of the trigeminal nerve tumor was performed. Histologically, the tumor consisted of highly cellular, spindle-shaped cells arranged in a fascicular pattern, with occasional mitotic figures, nuclear pleomorphism and necrosis. Immunohistochemically, the tumor cells showed variable intensities and frequencies of reactivity for S-100 protein, myelin basic protein, CD34, podoplanin and p53, but no reactivity for Smarcb1. Thus, the tumor exhibited features of MPNST. This case appears to provide information that is useful for accurate diagnosis and surgical planning in patients with bilateral or multiple cranial nerve tumors.

Update on Selected High-grade Renal Cell Carcinomas of the Kidney: FH-deficient, ALK-rearranged, and Medullary Carcinomas

High-grade renal cell carcinoma (RCC), often diagnosed at advanced stages, significantly contributes to renal cancer-related mortality. This review explores the progress in understanding specific subtypes of high-grade RCC, namely fumarate hydratase (FH)-deficient RCC, anaplastic lymphoma kinase (ALK)-rearranged RCC, and SMARCB1-deficient renal medullary carcinoma, all of which are now recognized as molecularly defined entities in the WHO classification system (2022). While these entities each exhibit a morphologic spectrum that overlaps with other high-grade RCC, ancillary tools developed based on their distinctive molecular alterations can help establish a specific diagnosis, underscoring the importance of integrating molecular findings into diagnostic paradigms. It is important to exclude these specific tumor types in cases with similar morphologic spectrum before rendering a diagnosis of high-grade papillary RCC, collecting duct carcinoma, or RCC, NOS. Several gray areas exist within the spectrum of high-grade uncommon types of RCC, necessitating continued research to enhance diagnostic precision and therapeutic options.

Loss of CDKN1C in a Recurrent Atypical Teratoid/Rhabdoid Tumor

Atypical teratoid/rhabdoid tumor (AT/RT) is a malignant tumor that is commonly associated with biallelic alterations of SMARCB1. Recurrent or refractory AT/RT has not been molecularly characterized as well. We present the case of a child with recurrent AT/RT who underwent clinically integrated molecular profiling (germline DNA and tumor DNA/RNA sequencing). This demonstrated a somatic lesion in CDKN1C alongside hallmark loss of SMARCB1. This data allowed us to explore potential personalized therapies for this patient and expose a molecular driver that may be involved in similar cases.

A Case of SMARCB1-Deficient Sinonasal Carcinoma With Clear Cell Morphology

SMARCB1 is a gene known to cause carcinogenesis in many soft tissue tumors, including malignant rhabdoid tumors and epithelioid sarcoma. Since the first report of a subtype of sinonasal carcinoma characterized by a deficiency of the SMARCB1 gene in 2014 to date, fewer than 200 cases have been reported. We report a case of SMARCB1-deficient sinonasal carcinoma with clear cell morphology. In our case, there are no evident basaloid or plasmacytoid/rhabdoid tumor cells, which are typical histopathological features of SMARCB1-deficient sinonasal carcinoma. SMARCB1-deficient sinonasal carcinoma is prone to recurrence and has a very poor prognosis. As the development of molecularly targeted agents progresses, therapeutic efficacy is expected to improve. Simultaneously, the importance of early and accurate diagnosis of SMARCB1-deficient sinonasal carcinoma will increase. With the limited information provided by biopsy specimens, it is necessary to confirm the loss of SMARCB1 expression by immunohistochemistry and investigate the presence of SMARCB1 gene deletion by molecular genetics, considering the possibility of SMARCB1-deficient sinonasal carcinoma even in atypical cases without basaloid or plasmacytoid/rhabdoid cell morphology, as in our case.

SWI/SNF-Related Matrix-Associated Actin-Dependent Regulator of Chromatin Subfamily B Member 1 (SMARCB1)-Deficient Tumor in the Parapharyngeal Space: A Case Report

SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1 (SMARCB1) is a tumor suppressor gene, and SMARCB1 deficits have been associated with numerous malignant tumors. Carcinomas with a SMARCB1 deficit generally have a poor prognosis. In the head and neck region, there have been many recent cases of SMARCB1-deficient sinonasal carcinoma, but reports of extrasinonasal sites are extremely rare. This study reports a case of SMARCB1-deficient tumor in the right parapharyngeal space. A 64-year-old woman with right neck swelling was presented to our hospital, and imaging revealed a tumor in the right parapharyngeal space. After four years of follow-up, the tumor had increased in size, and a biopsy revealed deficits in SMARCB1 in the tumor cells. No definitive histological diagnoses were made. Radiation reduced the size of the tumor, and the patient survived without progression, three years after completion of treatment.

Integrase Interactor 1 (INI1) Deficiency in a Lung Cancer Patient Presents Nonresponse to Immunotherapy and Tazemetostat: A Case Report

Integrase interactor 1 (INI1)-deficient lung cancer is extremely rare, often with poor prognosis, and lacks effective treatment. Previous studies have reported the efficacy of immunotherapy and enhancer of the zeste homolog 2 (EZH2) inhibitor tazemetostat in various types of INI1-deficient tumors, such as sarcomas. However, the effectiveness of these treatments in INI1-deficient lung cancer has not yet been verified. We hereby report a case of a patient who was diagnosed with advanced squamous lung cancer with INI1 deficiency and received chemotherapy, immunotherapy, and tazemetostat treatments successively. The patient showed optimal response in the initial chemotherapy combined with anti-programmed cell death protein 1 (PD-1) immunotherapy, made rapid progress in the subsequent stage of maintenance immunotherapy, and showed nonresponse to tazemetostat. To the best of our knowledge, this is the first case of a lung cancer patient with INI1 deficiency who received tazemetostat treatment.

High-Grade Atypical Teratoid/Rhabdoid Tumor in the Pituitary Region

Atypical teratoid/rhabdoid tumors (AT/RTs) are embryological tumors of the central nervous system (CNS). They are typically found in children, with rare presentations in adults. We describe the presentation of an AT/RT in the pituitary region of a 37-year-old female. The patient presented with a two-week history of intractable cephalgia with sudden onset of monocular diplopia and left-sided cranial nerve VI palsy. The patient underwent transsphenoidal resection of their mass, which revealed the diagnosis. She then underwent systemic therapy with chemotherapy as well as radiation. She ultimately died 14 months after treatment completion due to unrelated events. The case highlights the rarity of AT/RT in adults, emphasizing the challenge of establishing standardized treatment protocols due to its rarity in adult presentations.

Atypical Teratoid/Rhabdoid Tumor of the Sellar Region in an Adult Male: A Case Report

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare, fast-growing, aggressive tumor that is almost exclusively seen in the pediatric population; it has a poor prognosis despite aggressive treatment. Adult cases were thought to be exclusively of women, with a total of 23 cases reported worldwide. We herein report a case of a 35-year-old male who posed a unique clinical and diagnostic challenge. To the best of our knowledge, this is the third case of a male patient with sellar AT/RT in the world.

Orbital Apex Syndrome Secondary to SMARCB1-Deficient Invasive Sinonasal Carcinoma

Orbital apex syndrome (OAS) is a clinical entity defined by ophthalmoplegia and optic nerve dysfunction due to local disruption of the orbital apex. The causes of OAS are extensive and include infectious, inflammatory, traumatic, iatrogenic, and neoplastic conditions. Thus, appropriate management is dependent on an accurate and timely diagnosis of the underlying etiology. We present a case of a 58-year-old female who presented to the emergency department with ophthalmoplegia of subacute onset and diminished visual acuity in the setting of two weeks of headache, ocular pain, and facial swelling. She was ultimately diagnosed with OAS and admitted to the hospital for five days for further evaluation. She was found to have an incurable primary SMARCB1-deficient sinonasal carcinoma with an invasion of her orbital apex. A multidisciplinary management approach involving chemotherapy, radiation, and surgical intervention was performed, and the patient responded well. Nearly two years after her diagnosis, she continues to have stable residual carcinoma without evidence of recurrence or metastatic disease. Her visual acuity has returned to normal limits, and her oculomotor function has returned to near-normal levels.

Integrase Interactor 1 (INI-1) Deficient Renal Cell Carcinoma

Members of the SWItch/sucrose nonfermentable (SWI-SNF) family, including SWI/SNF related, matrix-associated, actin-dependent regulator of chromatin, subfamily A, member 4 (SMARCA4), SWI/SNF related, matrix‐associated, actin‐dependent regulator of chromatin, subfamily B member 1 (SMARCB1)/integrase interactor 1 (INI-1) are known tumor suppressor genes. Interactions between SMARCB1/INI-1 and key protein components in various cellular pathways are related to tumor progression and proliferation.SMARCB1/INI-1 protein was undetectable in rhabdoid tumor cells, whereas non-tumorous cells express the SMARCB1/INI-1 genes. Germline and sporadic mutations of several genes encoding for proteins in this complex are known to cause a spectrum of cancers, usually with sarcomatoid features which include a very aggressive renal medullary carcinoma. We report a case of a 29-year-old male who presented with SMARCA4 deficient renal tumor with a very aggressive clinical behavior which ultimately led to his death.

Coffin-Siris Syndrome and SMARCB1 Mutation Presenting With Schwannomatosis: A Case Report and Literature Review

Coffin-Siris syndrome (CSS) is a rare genetic condition associated with mutations in genes responsible for the modulation of gene expression and chromatin remodeling. Patients with CSS commonly present with congenital anomalies, intellectual disabilities, and developmental delays. We describe a case of a 28-year-old woman with a confirmed diagnosis of CSS and SMARCB1 mutation who presents with multiple schwannomas and an intra-abdominal neurofibroma. The patient underwent embolization and resection of an enlarging, symptomatic schwannoma of her left medial upper arm. In detailing the patient's presentation, this case report underscores the association between SMARCB1 mutations, CSS, and tumorigenesis.

A Rare Case of Rhabdoid Pancreatic Carcinoma: Prolonged Disease-Free Survival Following Upfront Resection and Adjuvant Chemotherapy

The rhabdoid subtype of undifferentiated pancreatic carcinoma is rarely reported. The clinical course of this disease is therefore poorly understood, although it is apparently an aggressive malignancy. We herein discuss the case of a 69-year-old man presenting with a rapidly enlarging mass of the pancreatic body and tail who was diagnosed with locally advanced SMARCB1-deficient undifferentiated pancreatic carcinoma with rhabdoid features, treated with radical resection and adjuvant chemotherapy, and has achieved 18-month disease-free survival ongoing at the time of article publication. We identify and contrast our case with 15 similar tumors reported in the English literature, briefly discuss the biology of this tumor, its relationship to malignant rhabdoid tumors of childhood, the role of SMARCB1 and its parent complex switch/sucrose-non-fermentable chromatin remodeling complex (SWI/SNF) in modulating the behavior of pancreatic malignancy, and the potential therapeutic avenues available for SWI/SNF-mutated malignancies.

Congenital Disseminated Malignant Rhabdoid Tumor Mimicking a Vascular Lesion

A congenital disseminated malignant rhabdoid tumor (MRT) is an exceedingly rare and aggressive pediatric cancer marked by the presence of malignant rhabdoid cells in various organs, including the brain, kidneys, and soft tissues, at birth. It is often detected prenatally or shortly post-birth. The malignancy's aggressiveness results in a bleak prognosis, offering limited treatment options and low survival rates. Early diagnosis and comprehensive medical intervention are crucial, but managing this condition is complicated by its rarity. We herein presented a case of a 37 and 1/7 week gestation male infant with a rapidly growing arm soft tissue mass within two weeks, diagnosed as an MRT. Post-delivery examinations revealed multiple lesions in the lungs, kidney, liver, and adrenal glands. Notably, chemotherapy yielded a significant improvement in the arm lesion, contrasting with other lesions showing a limited response. This observation suggests potential tumor heterogeneity, emphasizing the necessity of diverse therapeutic regimens. Our case underscores the complexities of congenital disseminated MRT, prompting a reevaluation of treatment strategies for enhanced efficacy in managing this challenging pediatric cancer.