BACKGROUND: Uterine tumors resembling ovarian sex cord tumors (UTROSCT) with rhabdoid features are uncommon mesenchymal neoplasms exhibiting diverse histological patterns, including significant rhabdoid morphology. A thorough comprehension of their clinicopathologic features is crucial for precise diagnosis and effective management.
METHODS: This study presents 4 cases of UTROSCT with rhabdoid features, diagnosed in patients aged 31 to 58. Varied recurrence patterns were observed, including similar recurrent lesions to the primary tumors with subsequent mortality, initial invasion and lymph node metastasis, and presence of only primary tumor.
METHODS: Histopathological examination revealed diverse morphological patterns, prominently featuring rhabdoid differentiation. Immunohistochemical analysis showed expression of hormone receptors, sex cord, smooth muscle, and epithelial markers, notably WT1, CD56, and CD99. Molecular analysis identified ESR1-NCOA2 fusions and ESR1 and NCOA2/3 rearrangements, indicating a potential association between these genetic alterations and extensive rhabdoid differentiation.
METHODS: Various treatments were administered post-recurrence, including chemotherapy and targeted therapies. However, poor clinical outcomes were observed in all cases.
RESULTS: Despite aggressive treatments, including chemotherapy and targeted therapies, poor clinical outcomes were observed, highlighting the aggressive nature of UTROSCT with significant rhabdoid differentiation.
CONCLUSIONS: This case series emphasizes the importance of detailed pathological reporting, comprehensive molecular testing, and thorough tumor staging in UTROSCT cases with rhabdoid features. Enhanced understanding of the clinicopathologic characteristics of UTROSCT with rhabdoid differentiation is crucial for accurate diagnosis, prognostication, and management strategies.

BACKGROUND: Survival data for recurrent pediatric atypical teratoid rhabdoid tumor (ATRT) and its association to molecular groups are extremely limited.
METHODS: Single-institution retrospective study of 64 children less than 21 years old with recurrent or treatment-refractory (progressive disease [PD]) ATRT treated at St. Jude Hospital from January 2000 to December 2020. Demographic, clinicopathologic, treatment, molecular grouping (SHH, TYR, and MYC) and germline data were collected. Progression-free survival (PFS2: time from PD to subsequent first progression) and overall survival (OSpostPD: time from PD to death/last follow-up) were estimated by Kaplan-Meier analysis.
RESULTS: Median age at and time from initial diagnosis to PD were 2.1 years (range: 0.5-17.9 years) and 5.4 months (range: 0.5-125.6 months), respectively. Only five of 64 children (7.8%) are alive at median follow-up of 10.9 (range: 4.2-18.1) years from PD. The 2/5-year PFS2 and OSpostPD were 3.1% (±1.8%)/1.6% (±1.1%) and 20.3% (±4.8%)/7.3% (±3.5%), respectively. Children with TYR group (n = 10) had a better OSpostPD compared to those with MYC (n = 11) (2-year survival estimates: 60.0% ± 14.3% vs. 18.2% ± 9.5%; p = .019), or those with SHH (n = 21; 4.8% ± 3.3%; p = .014). In univariate analyses, OSpostPD was better with older age at diagnosis (p = .037), female gender (p = .008), and metastatic site of PD compared to local or combined sites of PD (p < .001). Two-year OSpostPD for patients receiving any salvage therapy (n = 39) post PD was 33.3% ± 7.3%.
CONCLUSIONS: Children with recurrent/refractory ATRT have dismal outcomes. Older age at diagnosis, female gender, TYR group, and metastatic site of PD were associated with relatively longer survival in our study.

It has been suggested that most, if not all, extrarenal rhabdoid tumors of the vulva represent \"proximal-type\" epithelioid sarcomas. To better understand rhabdoid tumors of the vulva, we studied the clinicopathologic, immunohistochemical (IHC), and molecular features of 8 of these tumors and 13 extragenital epithelioid sarcomas. IHC analysis for cytokeratin AE1/AE3, EMA, S100, CD34, ERG, smooth muscle actin, desmin, and SMARCB1 (INI1) was performed. Ultrastructural study was done in one vulvar rhabdoid tumor. Next-generation sequencing of the SMARCB1 gene was performed in all cases. The 8 vulvar tumors occurred in adult women (mean age, 49 years). They were poorly differentiated neoplasms with a rhabdoid morphology. The ultrastructural study showed large amounts of intermediate filaments (10 nm). All cases had loss of expression of INI1 and were negative for CD34 and ERG. One case showed 2 SMARCB1 mutations: c.592C>T in exon 5 and c.782delG in exon 6. Follow-up revealed that 4 patients died of disease, 1 was alive with disease, and 3 were alive without evidence of disease. Epithelioid sarcomas occurred in young adults (mean age, 41 years), mostly men. Seven tumors arose in the distal extremities and the other 6 had a proximal location. They showed the characteristic \"granulomatous\" arrangement of the neoplastic cells. The recurrent tumors were more proximal and often showed a rhabdoid morphology. All cases had loss of expression of INI1. CD34 and ERG were expressed by 8 (62%) and 5 (38%) tumors, respectively. No SMARCB1 mutations were encountered. Follow-up revealed that 5 patients died of disease, 1 was alive with disease, and 7 were alive without evidence of disease. Based on their different morphology and biological behavior, we conclude that rhabdoid tumors of the vulva and epithelioid sarcomas are different diseases with distinct clinicopathologic features. Undifferentiated vulvar tumors with rhabdoid morphology should be classified as malignant rhabdoid tumors, rather than \"proximal-type\" epithelioid sarcomas.

To discuss the clinical and prognostic indicators of pediatric malignant rhabdoid tumor of the kidney (MRTK), and to increase the understanding of the occurrence and development of MRTK.
From July 2014 to September 2021, all cases were confirmed by postoperative pathological examination. Among the 42 patients, there were 25 males and 17 females, with a median age of 10 (1-84) months. Abdominal mass or hematuria were the main clinical manifestations. Preoperative chemotherapy was performed in 9 cases (VC). The tumor stages were stage I-IV. Preoperative metastasis was found in 9 cases; the most common site was the lung. Postoperative patients received conventional chemotherapy, including VDACE regimen and UH-1 regimen. Among the 42 children in this group, survival at follow-up in this study was 26.2%(11/42).
Preoperative anemia was found by univariate analysis, hypertension and hypercalcemia had shorter survival time. In addition, tumor-related factors had a significant impact on survival, with incomplete tumor resection, lymph node metastasis, stage III-IV had a lower survival rate. The impact of postoperative factors on survival included postoperative complications had a lower survival rate. The children were younger than 12 months, preoperative metastasis, no chemotherapy was performed after surgery was an independent risk factor for the prognosis of MRTK.
The main clinical manifestations about MRTK were abdominal mass and hematuria. Preoperative chemotherapy did not significantly improve the prognosis. Postoperative chemotherapy can significantly improve the survival rate. Diagnosis depends on clinical manifestations, imaging, histopathology, immunohistochemistry and other comprehensive judgment. Age less than 12 months, preoperative metastasis, and no postoperative chemotherapy were independent risk factors for prognosis.

OBJECTIVE: This study aimed to evaluate the application of apparent diffusion coefficient (ADC) histogram analysis to differentiate posterior fossa tumors (PFTs) in children.
METHODS: A total of 175 pediatric patients with PFT, including 75 pilocytic astrocytomas (PA), 59 medulloblastomas, 16 ependymomas, and 13 atypical teratoid rhabdoid tumors (ATRT), were analyzed. Tumors were visually assessed using DWI trace and conventional MRI images and manually segmented and post-processed using parametric software (pMRI). Furthermore, tumor ADC values were normalized to the thalamus and cerebellar cortex. The following histogram metrics were obtained: entropy, minimum, 10th, and 90th percentiles, maximum, mean, median, skewness, and kurtosis to distinguish the different types of tumors. Kruskal Wallis and Mann-Whitney U tests were used to evaluate the differences. Finally, receiver operating characteristic (ROC) curves were utilized to determine the optimal cut-off values for differentiating the various PFTs.
RESULTS: Most ADC histogram metrics showed significant differences between PFTs (p < 0.001) except for entropy, skewness, and kurtosis. There were significant pairwise differences in ADC metrics for PA versus medulloblastoma, PA versus ependymoma, PA versus ATRT, medulloblastoma versus ependymoma, and ependymoma versus ATRT (all p < 0.05). Our results showed no significant differences between medulloblastoma and ATRT. Normalized ADC data showed similar results to the absolute ADC value analysis. ROC curve analysis for normalized ADCmedian values to thalamus showed 94.9% sensitivity (95% CI: 85-100%) and 93.3% specificity (95% CI: 87-100%) for differentiating medulloblastoma from ependymoma.
CONCLUSIONS: ADC histogram metrics can be applied to differentiate most types of posterior fossa tumors in children.

Recurrent atypical teratoid/rhabdoid tumor (AT/RT) is, most often, a fatal pediatric malignancy with limited curative options.
We conducted a phase II study of Aurora kinase A inhibitor alisertib in patients aged <22 years with recurrent AT/RT. Patients received alisertib once daily (80 mg/m2 as enteric-coated tablets or 60 mg/m2 as liquid formulation) on Days 1-7 of a 21-day cycle until progressive disease (PD) occurred. Alisertib plasma concentrations were measured in cycle 1 on Days 1 (single dose) and 7 (steady state) and analyzed with noncompartmental pharmacokinetics. Trial efficacy end point was ≥10 participants with stable disease (SD) or better at 12 weeks.
SD (n = 8) and partial response (PR) (n = 1) were observed among 30 evaluable patients. Progression-free survival (PFS) was 30.0% ± 7.9% at 6 months and 13.3% ± 5.6% at 1 year. One-year overall survival (OS) was 36.7% ± 8.4%. Two patients continued treatment for >12 months. PFS did not differ by AT/RT molecular groups. Neutropenia was the most common adverse effect (n = 23/30, 77%). The 22 patients who received liquid formulation had a higher mean maximum concentration (Cmax) of 10.1 ± 3.0 µM and faster time to Cmax (Tmax = 1.2 ± 0.7 h) than those who received tablets (Cmax = 5.7 ± 2.4 µM, Tmax = 3.4 ± 1.4 h).
Although the study did not meet predetermined efficacy end point, single-agent alisertib was well tolerated by children with recurrent AT/RT, and SD or PR was observed in approximately a third of the patients.

Extracranial malignant rhabdoid tumours are tumours that mainly affect young children and have a poor prognosis. In 2014, the European Paediatric Soft-tissue sarcoma Study Group developed treatment recommendations consisting in intensive dose chemotherapy every 2 weeks using vincristine-doxorubicin-cyclophosphamide (VDCy) and ifosfamide-etoposide (IE) associated with early surgery and irradiation of tumour sites.
A retrospective study was conducted on children treated in France by these new recommendations up to January 2019.
Thirty-five patients were identified. The primary tumour was in miscellaneous soft parts for 18 patients, in the kidney for 11 and in the liver for six. The median age at diagnosis was 17.5 months (range 1.2-198.2). Distant locations (metastatic or synchronous tumours) were present in 37.1% at diagnosis. SMARCB1 germline pathogenic variant was detected in 17.1% of patients. Overall tolerance was good, with 87-97% of theoretical chemotherapy cumulative doses actually delivered. The median interval between two courses was 18 days. Surgical resection was performed in 83% (19 R0, 7 R1 and 3 R2) and local radiotherapy in 49% of patients. After a median follow-up of 50.4 months (range 16.5-134.1), the 2-year overall and event-free survivals were 47.6% (95% confidence interval [CI] 30.2-63.1) and 42.9% (95% [CI] 26.5-58.3), respectively. On univariate analyses, localised disease and gross total resection were significantly associated with favourable outcomes.
Intensive dose chemotherapy with VDCy/IE can be administrated with no remarkable short-term toxicity, including in infants. However, the outcome remains poor for patients without gross total resection and with metastatic or multifocal disease. These patients could be stratified into a high-risk group that requires a new immediate therapeutic approach such as targeted agents combined with multimodal therapy.

Objective: Malignant rhabdoid tumor (MRT) is a rare but aggressive malignancy. It has been a long time since data on this tumor have been updated. Methods: We retrospectively reviewed patients from the SEER database who were pathologically diagnosed with MRT and analyzed incidence rates, clinical features and survival using Stata 12.0. Results: In total, 544 patients were included in the epidemiological analysis. There were two peak periods of MRT incidence: patients younger than 4 years and those older than 70 years. Further survival analysis showed that the survival of children (especially younger than 1 year) was markedly worse than that of adults (P<0.01), and different primary sites were associated with different age groups and survival outcomes. The central nervous system (CNS) was the most common primary site (50.00%), followed by the kidney (15.66%). Patients with MRTs that originated from the digestive system experienced worse survival outcomes than those with MRTs originating from other locations. Primary site surgery conferred survival benefits to patients with renal and digestive system MRTs (HR = 0.06, CI: 0.02-0.23, P<0.01; HR=0.10, CI: 0.02-0.48, P<0.01), whereas radiotherapy conferred benefits to patients with CNS, bone and soft tissue MRTs (HR=0.22, CI: 0.15-0.34, P<0.01; HR=0.44, CI: 0.21-0.90 P=0.03). Conclusions: Our results indicate that age and the primary site of MRT are critical clinical factors that affect patient survival and treatment choices. Primary site tumor resection should be considered for renal and digestive system MRTs, and systematic therapy, including surgery and radiotherapy, should be recommended for the treatment of CNS, bone and soft tissue MRTs.

Atypical teratoid/rhabdoid tumor (ATRT) is a rare and largely pediatric diagnosis, with poor survival. Diagnosis below the age of 3 years is characteristically seen as a poor prognostic sign. However, elucidating if clinical differences exist within this niche age group has never been attempted before. Correspondingly, we sought to characterize clinical profile of ATRT diagnoses before the age of 3 years based on separate ages of diagnosis.
All pediatric ATRT patients aged < 3 years in the US National Cancer Database (NCDB) between 2005 and 2016 were retrospectively reviewed. Age groups were divided based on diagnoses at ages 0-1 years in group 1, 1-2 years in group 2, and 2-3 years in group 3. Data were summarized, and overall survival (OS) was modeled using Kaplan-Meier and Cox regression analyses.
A total of 354 ATRT diagnoses were made before the age of 3 years, with surgery used in 316 (89%) cases, chemotherapy in 242 (68%) cases, and radiation therapy in 118 (33%) cases. In terms of diagnosis age, there were 153 (43%) in group 1, 137 (39%) in group 2, and 64 (18%) in group 3. With respect to OS, median value was 9.9 months in group 1, 28.4 months in group 2, and 15.9 months in group 3. Upon multivariate analysis, receiving radiation therapy was the only parameter shared amongst all three groups as independently prognostic of longer OS (HR 0.53, P = 0.01 in group 1; HR 0.34, P < 0.01 in group 2; HR 0.31, P < 0.01 in group 3). In group 1, surgery (HR 0.47, P < 0.01) and chemotherapy (HR 0.44, P < 0.01) were also independently prognostic of longer OS. In group 3, multiple socioeconomic parameters were identified to independently predict longer OS. There were no additional predictive parameters identified in group 2.
Although ATRT diagnosed before the age of 3 is typically viewed a poor prognostic age category, our findings demonstrate that the clinical profile of this pediatric niche is highly heterogeneous based on age of diagnosis. Survival of only those diagnosed between 0 and 1 years is independently prognosticated by all three treatment modalities; patients diagnosed between 1 and 2 years trend towards longest survival, and socioeconomic parameters are most influential in those diagnosed between 2 and 3 years.

Malignant renal tumours represent 5% of childhood cancers and include types with likely different aetiology: Wilms tumour (WT), rhabdoid renal tumour, kidney sarcomas and renal carcinomas. WT is the most common renal tumour in children, previously shown to vary internationally and with ethnicity. Using the comprehensive database of the International Incidence of Childhood Cancer study (IICC), we analysed global variations and time trends in incidence of renal tumour types in children (age 0-14 years) and adolescents (age 15-19 years). The results were presented by 14 world regions, and five ethnic groups in the US. We included 15 320 renal tumours in children and 800 in adolescents reported to the 163 contributing registries during 2001-2010. In children, age-standardised incidence rate (ASR) of renal tumours was 8.3 per million (95% confidence interval, CI = 8.1, 8.4); it was the highest in North America and Europe (9-10 per million) and the lowest in most Asian regions (4-5 per million). In the US, Blacks had the highest ASR (10.9 per million, 95% CI = 10.2, 11.6) and Asian and Pacific Islanders the lowest (4.4 per million, 95% CI = 3.6, 5.1). In adolescents, age-specific incidence rate of renal tumours was 1.4 per million (95% CI = 1.3, 1.5). WT accounted for over 90% of all renal tumours in each age from 1 to 7 years and the proportion of renal carcinomas increased gradually with age. From 1996 to 2010, incidence remained mostly stable for WT (average annual percent change, AAPC = 0.1) and increased for renal carcinomas in children (AAPC = 3.7) and adolescents (AAPC = 3.2). Our findings warrant further monitoring.