Clinicopathological characteristics and prognosis of uterine sarcoma: a 10-year retrospective single-center study in China.

BACKGROUND: Uterine sarcoma is a rare and heterogeneous gynecological malignancy characterized by aggressive progression and poor prognosis. The current study aimed to investigate the relationship between clinicopathological characteristics and the prognosis of uterine sarcoma in Chinese patients. METHODS: In this single-center retrospective study, we reviewed the medical records of 75 patients with histologically verified uterine sarcoma treated at the First Affiliated Hospital of Xi'an Jiaotong University between 2011 and 2020. Information on clinical characteristics, treatments, pathology and survival was collected. Progression-free survival (PFS) and overall survival (OS) were visualized in Kaplan-Meier curves. Prognostic factors were identified using the log-rank test for univariate analysis and Cox-proportional hazards regression models for multivariate analysis. RESULTS: The histopathological types included 36 endometrial stromal sarcomas (ESS,48%), 33 leiomyosarcomas (LMS,44%) and 6 adenosarcomas (8%). The mean age at diagnosis was 50.2 ± 10.7 years. Stage I and low-grade accounted for the majority. There were 26 recurrences and 25 deaths at the last follow-up. The mean PFS and OS were 89.41 (95% CI: 76.07-102.75) and 94.03 (95% CI: 81.67-106.38) months, respectively. Univariate analysis showed that > 50 years, post-menopause, advanced stage, ≥ 1/2 myometrial invasion, lymphovascular space invasion and high grade were associated with shorter survival (P < 0.05). Color Doppler flow imaging positive signals were associated with shorter PFS in the LMS group (P = 0.046). The ESS group had longer PFS than that of the LMS group (99.56 vs. 76.05 months, P = 0.043). The multivariate analysis showed that post-menopause and advanced stage were independent risk factors of both PFS and OS in the total cohort and LMS group. In the ESS group, diagnosis age > 50 years and high-grade were independent risk factors of PFS, while high-grade and lymphovascular space invasion were independent risk factors of OS. CONCLUSION: In Chinese patients with uterine sarcoma, post-menopause and advanced stage were associated with a significantly poorer prognosis. The prognosis of ESS was better than that of LMS. Color Doppler flow imaging positive signals of the tumor helped to identify LMS, which needs to be further tested in a larger sample in the future.

Safety and efficacy of fruquintinib-based therapy in patients with advanced or metastatic sarcoma.

BACKGROUND: The purpose of this study was to evaluate the efficacy and safety of fruquintinib-based therapy as a salvage therapy for patients with advanced or metastatic sarcoma, including soft tissue sarcoma (STS) and bone sarcoma. METHODS: Patients with advanced or metastatic sarcoma were divided into two groups. One group received fruquintinib monotherapy, while the other received fruquintinib combined therapy. Safety and efficacy of fruquintinib-based therapy were recorded and reviewed retrospectively, including progression-free survival (PFS), overall response rate (ORR), and adverse events (AEs). RESULTS: Between August 2021 and December 2022, 38 sarcoma patients were retrospectively included. A total of 14 patients received fruquintinib alone (including 6 STS and 8 bone sarcoma), while 24 were treated with fruquintinib combined therapy (including 2 STS and 22 bone sarcoma). The median follow-up was 10.2 months (95% CI, 6.4-11.5). For the entire population, the median PFS was 8.0 months (95% CI, 5.5-13.0). The ORR was 13.1%, while the disease control rate (DCR) was 86.8%. The univariate analysis showed that radiotherapy history (HR, 4.56; 95% CI, 1.70-12.24; p = 0.003), bone sarcoma (HR, 0.34; 95% CI, 0.14-0.87; p = 0.024), and treatment method of fruquintinib (HR, 0.36; 95% CI, 0.15-0.85; p = 0.021) were significantly associated with PFS. The multivariate analysis showed that patients without radiotherapy history were associated with a better PFS (HR, 3.71; 95% CI: 1.31-10.55; p = 0.014) than patients with radiotherapy history. Patients in combination group reported pneumothorax (8.3%), leukopenia (33.3%), thrombocytopenia (12.5%), diarrhea (4.2%), and anemia (4.2%) as the most frequent grade 3 or higher treatment-emergent AEs (TEAEs), while there was no severe TEAEs occurred in the monotherapy group. CONCLUSIONS: Fruquintinib-based therapy displayed an optimal tumor control and an acceptable safety profile in patients with advanced or metastatic sarcoma.

Pulmonary sarcomatoid carcinoma: A rare case report, diagnostic dilemma and review of literature.

RATIONALE: Pulmonary sarcomatoid carcinoma (PSC), a rare tumor, comprises 0.1% to 0.4% of all malignant lung tumors. Given the rarity of PSC, its clinical course, therapeutic guidelines, and patient outcomes remain largely unknown. Therefore, it is imperative to alert clinicians to this extremely rare and instructive early-onset cancer. PATIENT CONCERNS: This report describes a 28-year-old woman with PSC, who was initially misdiagnosed with Whipple's disease. A conclusive diagnosis of PSC was made following careful clinical examination, imaging, and histopathological evaluation of the patient's biopsy sample. Radiological imaging revealed multiple nodules and mass formations in the left upper lobe of the patient's lung, with the largest measuring of 5.4 × 3.2 cm. DIAGNOSIS: Histopathological examination indicated the presence of a malignant neoplasm associated with necrosis suggestive of sarcoma, which was pathologically staged as cT4N1M1. INTERVENTIONS AND OUTCOMES: A regimen of doxorubicin and ifosfamide was administered therapeutically, resulting in a stable disease state. LESSONS: The rarity and tumor origin challenge the diagnosis, which emphasizes the imperative role of histological examination, immunohistochemistry, and flow cytometry in achieving an accurate diagnosis. This report summarizes the existing publications to provide a comprehensive overview of PSC, including its clinical manifestations, radiographic imaging, pathologic features, diagnostic challenges, treatment strategies, and prognosis, and aims to improve the understanding of PSC.

Primary pulmonary myxoid sarcoma in the interlobar fissure of the left lung lobe: a case report.

BACKGROUND: Primary pulmonary myxoid sarcoma (PPMS) is a rare, low-grade malignant tumor, constituting approximately 0.2% of all lung tumors. Despite its rarity, PPMS possesses distinctive histological features and molecular alterations, notably the presence of EWSR1-CREB1 gene fusion. However, its precise tissue origin remains elusive, posing challenges in clinical diagnosis. CASE DEMONSTRATION: A 20-year-old male patient underwent a routine physical examination 6 months prior, revealing a pulmonary mass. Following surgical excision, microscopic evaluation unveiled predominantly short spindle-shaped tumor cells organized in a fascicular, beam-like, or reticular pattern. The stromal matrix exhibited abundant mucin, accompanied by lymphocytic and plasma cell infiltration, with Russell bodies evident in focal areas. Immunophenotypic profiling revealed positive expression of vimentin and epithelial membrane antigen in tumor cells, whereas smooth muscle actin and S-100, among others, were negative. Ki-67 proliferation index was approximately 5%. Subsequent second-generation sequencing identified the characteristic EWSR1-CREB1 gene fusion. The definitive pathological diagnosis established PPMS. The patient underwent no adjuvant chemotherapy or radiotherapy and remained recurrence-free during a 30-month follow-up period. CONCLUSIONS: We report a rare case of PPMS located within the left lung lobe interlobar fissure, featuring Russell body formation within the tumor stroma, a novel finding in PPMS. Furthermore, the histomorphological characteristics of this case highlight the diagnostic challenge it poses, as it may mimic inflammatory myofibroblastic tumor, extraskeletal myxoid chondrosarcoma, or hemangiopericytoma-like fibrous histiocytoma. Therefore, accurate diagnosis necessitates an integrated approach involving morphological, immunohistochemical, and molecular analyses.

A clinical tool to predict overall survival of elderly patients with soft tissue sarcoma after surgical resection.

With the aging world population, the incidence of soft tissue sarcoma (STS) in the elderly gradually increases and the prognosis is poor. The primary goal of this research was to analyze the relevant risk factors affecting the postoperative overall survival in elderly STS patients and to provide some guidance and assistance in clinical treatment. The study included 2,353 elderly STS patients from the Surveillance, Epidemiology, and End Results database. To find independent predictive variables, we employed the Cox proportional risk regression model. R software was used to develop and validate the nomogram model to predict postoperative overall survival. The performance and practical value of the nomogram were evaluated using calibration curves, the area under the curve, and decision curve analysis. Age, tumor primary site, disease stage, tumor size, tumor grade, N stage, and marital status, are the risk variables of postoperative overall survival, and the prognostic model was constructed on this basis. In the two sets, both calibration curves and receiver operating characteristic curves showed that the nomogram had high predictive accuracy and discriminative power, while decision curve analysis demonstrated that the model had good clinical usefulness. A predictive nomogram was designed and tested to evaluate postoperative overall survival in elderly STS patients. The nomogram allows clinical practitioners to more accurately evaluate the prognosis of individual patients, facilitates the progress of individualized treatment, and provides clinical guidance.

Neurotrophic tyrosine receptor kinase gene fusions in adult and pediatric patients with solid tumors: a clinicogenomic biobank and record linkage study of expression frequency and patient characteristics from Finland.

BACKGROUND: Neurotrophic tyrosine receptor kinase (NTRK) gene fusions are oncogenic drivers. Using the Auria Biobank in Finland, we aimed to identify and characterize patients with these gene fusions, and describe their clinical and tumor characteristics, treatments received, and outcomes. MATERIAL AND METHODS: We evaluated pediatrics with any solid tumor type and adults with colorectal cancer (CRC), non-small cell lung cancer (NSCLC), sarcoma, or salivary gland cancer. We determined tropomyosin receptor kinase (TRK) protein expression by pan-TRK immunohistochemistry (IHC) staining of tumor samples from the Auria Biobank, scored by a certified pathologist. NTRK gene fusion was confirmed by next generation sequencing (NGS). All 2,059 patients were followed-up starting 1 year before their cancer diagnosis. RESULTS: Frequency of NTRK gene fusion tumors was 3.1% (4/127) in pediatrics, 0.7% (8/1,151) for CRC, 0.3% (1/288) for NSCLC, 0.9% (1/114) for salivary gland cancer, and 0% (0/379) for sarcoma. Among pediatrics there was one case each of fibrosarcoma (TPM3::NTRK1), Ewing's sarcoma (LPPR1::NTRK2), primitive neuroectodermal tumor (DAB2IP::NTRK2), and papillary thyroid carcinoma (RAD51B::NTRK3). Among CRC patients, six harbored tumors with NTRK1 fusions (three fused with TPM3), one harbored a NTRK3::GABRG1 fusion, and the other a NTRK2::FXN/LPPR1 fusion. Microsatellite instability was higher in CRC patients with NTRK gene fusion tumors versus wild-type tumors (50.0% vs. 4.4%). Other detected fusions were SGCZ::NTRK3 (NSCLC) and ETV6::NTRK3 (salivary gland cancer). Four patients (three CRC, one NSCLC) received chemotherapy; one patient (with CRC) received radiotherapy. CONCLUSION: NTRK gene fusions are rare in adult CRC, NSCLC, salivary tumors, sarcoma, and pediatric solid tumors.

Müllerian adenosarcoma with sarcomatous overgrowth and heterologous elements: A case report and literature review.

Uterine mullerian adenosarcoma (MA) is a rare biphasic tumour that accounts for less than 0.5% of uterine neoplasms. The age range of presentation is wide, with the median age in the 5th decade of life. It usually has a good prognosis; however, it worsens when it presents with sarcomatous overgrowth, heterologous elements or infiltrates the myometrium. We report the case of a 63-year-old woman presenting with abnormal vaginal bleeding and a sensation of solid material coming out of the cervical canal who was diagnosed with mullerian adenosarcoma with sarcomatous overgrowth (MASO) and presence of heterologous elements after performing a mass biopsy and subsequent hysterectomy. We reviewed the literature, focusing especially on the differential diagnoses to be evaluated, as well as the differences in prognosis and treatment according to whether or not they present histologic features of poor prognosis.

Uncommon adrenal rest tumors and massive adrenal enlargement in adult with congenital adrenal hyperplasia mimicking metastasis from pleomorphic sarcoma.

BACKGROUND: Congenital adrenal hyperplasia (CAH) encompassed a bunch of autosomal recessive disorders characterized by impaired cortisol levels due to an enzymatic deficiency in steroid synthesis. In adult male patients with CAH, a frequent complication related to poor disease control is the development of ectopic adrenocortical tissue in the testes, named testicular adrenal rest tumors (TART). Conversely, ovarian adrenal rest tumors (OART) in females are extremely rare and adrenal rests in sites other than gonads are so uncommon to have been described only few times in literature. CASE PRESENTATION: We report a case of a male patient with untreated CAH and oncologic history of pleomorphic sarcoma who presented with massive bilateral adrenal enlargement and adrenal rest tumors in peri-lumbar and peri-cecal sites, which mimicked metastasis from sarcoma. CONCLUSIONS: The development of massive adrenal enlargement and ectopic adrenal rest tumors in sites other than gonads, even if very uncommon, should be suspected in patients with CAH and prolonged periods of undertreatment.

Discordance Between the Initial Diagnosis of Sarcomas and Subsequent Histopathological Revision and Molecular Analyses in a Sarcoma Reference Center in Brazil.

PURPOSE: To investigate the discordance in sarcoma diagnoses between nonspecialized institutions following revision by dedicated sarcoma pathologists at a reference center in Brazil and the relevance of molecular pathology in this context. METHODS: We conducted a retrospective analysis of sarcoma samples initially analyzed at outside laboratories and subsequently reviewed by two specialized pathologists between January 2014 and December 2020. After obtaining demographic and tumor characteristics, pathology results were matched and classified as complete discordance (CD; benign v malignant, sarcoma v other malignancies), partial concordance (similar diagnosis of connective tumor, but different grade/histological subtype/differentiation), and complete concordance (CC). The concordance for histology or grade, and the role of molecular assessments supporting the diagnosis were also independently determined. Statistical analyses were conducted through the kappa coefficient of agreement and adherence by χ2 test, χ2 test by Person, and Fisher exact test. RESULTS: In total, 197 cases were included, with samples obtained predominately from male patients (57.9%) and localized/primary tumors (86.8%). Following revision, the most frequent final diagnoses were undifferentiated pleomorphic sarcoma (17.8%), well-differentiated/dedifferentiated liposarcoma (8.6%), and leiomyosarcoma (7.6%). CD was found in 13.2%, partial discordance in 45.2%, and CC in 41.6% of reviews (P < .001). We found a concordance for histology or grade of 53.5% (P < .001) and 51.8% (P < .001), respectively. Molecular assessments, comprising next-generation sequencing panels (79.5%) and fluorescent in situ hybridization (20.5%), were performed in 44 (22.3%) cases, with findings classified as of diagnostic relevance in 31.8%. CONCLUSION: In nearly 60% of the cases, the initial sarcoma diagnosis was modified when revised by a reference center and dedicated pathologists, assisted by molecular pathology techniques. These results justify the assembly of referral networks in countries with limited health care resources.

Survival and prognostic factors of primary retroperitoneal sarcomas after surgery: a single-center experience.

PURPOSE: The percentage of retroperitoneal sarcomas (RPS) among all soft tissue sarcomas ranges from 10 to 15%. Surgery remains the gold standard for RPS. In this study, we analyzed the impact of surgical treatment for primary RPS on recurrence and overall mortality at a Chinese institution and identified and evaluated prognostic variables. METHODS: Data from patients with RPS who underwent surgical treatment were retrospectively analyzed. The patients were treated at a single center from January 2000 to June 2018. Retrospectively collected demographic, clinicopathological, and surgical factors were examined. Overall survival (OS) and disease-free survival (DSF) were used as the primary endpoints. Predicted 5-year survival rates, encompassing both DFS and OS, were derived from the Sarculator prognostic nomogram. RESULTS: A total of 110 patients met the inclusion criteria. The median follow-up time after surgery for patients with primary RPS was 5.3 years. During this period, 59 patients died. The 5-year OS and DFS estimates were 63.5% and 35.3%, respectively. In a multivariate analysis, poor OS following surgical treatment of primary RPS was independently correlated with FNCLCC grade (p < 0.001) and surgical margin status (p = 0.016). FNCLCC grade (p = 0.001) and surgical margin status (p = 0.002) were also independently associated with poor DFS. The C-indices for 5-year OS and DFS survival utilizing the Sarculator prognostic nomogram were 0.71 and 0.73 respectively. CONCLUSION: The overall mortality rate of patients with RPS was considered acceptable. OS and DFS prognostic markers were established for primary RPS. Tumor grade and intraregional margins are other factors that affect survival and recurrence.

Rapid but nondurable response of a BRAF exon 15 double-mutated spindle cell sarcoma to a combination of BRAF and MEK inhibitors.

INTRODUCTION: BRAF V600E substitution predicts sensitivity of a cancer to BRAF inhibitor therapy. The mutation is rarely found in soft-tissue sarcomas. Here we describe a case of undifferentiated spindle cell sarcoma showing primary insensitivity to standard chemotherapy and pronounced but non-sustained response to BRAF/MEK inhibitors at recurrence. CASE PRESENTATION: A 13-year-old girl was diagnosed with low-grade spindle cell sarcoma of pelvic localization, BRAF exon 15 double-mutated: c.1799T>A p.V600E and c.1819T>A p.S607T in cis-position. The tumor showed resistance to CWS-based first-line chemotherapy and was treated surgically by radical resection. Seven months after surgery the patient developed metastatic relapse with abdominal carcinomatosis. Combined targeted therapy with BRAF/MEK inhibitors afforded complete response in 1 month and was continued, though complicated by severe side effects (fever, rash) necessitating 1-2 week toxicity breaks. After 4 months from commencement the disease recurred and anti-BRAF/MEK regimen consolidation was unsuccessful. Intensive salvation chemotherapy was ineffective. Empirical immunotherapy afforded a transient partial response giving way to fatal progression with massive, abdominal cocoon-complicated peritoneal carcinomatosis. CONCLUSION: This is the first report of spindle cell sarcoma BRAF V600E/S607T double-mutated, responding to a combination of B-Raf and MEK inhibitors. Despite the low histological grade and radical surgical treatment of the tumor at primary manifestation, the disease had aggressive clinical course and the response to BRAF/MEK targeted therapy at recurrence was complete but nondurable. Empirical use of pembrolizumab provided no unambiguous evidence on the clinical relevance of immunotherapy in protein kinase -rearranged spindle cell tumors.

Expanding the Spectrum of NUTM1 -Rearranged Sarcoma : A Clinicopathologic and Molecular Genetic Study of 8 Cases.

Apart from the lethal midline carcinoma (NUT carcinoma), NUTM1 translocation has also been reported in mesenchymal tumors, but is exceedingly rare. Here, we describe a series of 8 NUTM1 -rearranged sarcomas to further characterize the clinicopathologic features of this emerging entity. This cohort included 2 males and 6 females with age ranging from 24 to 64 years (mean: 51 y; median: 56 y). Tumors occurred in the colon (2), abdomen (2), jejunum (1), esophagus (1), lung (1) and infraorbital region (1). At diagnosis, 6 patients presented with metastatic disease. Tumor size ranged from 1 to 10.5 cm (mean: 6 cm; median: 5.5 cm). Histologically, 4 tumors were composed of primitive small round cells to epithelioid cells intermixed with variable spindle cells, while 3 tumors consisted exclusively of small round cells to epithelioid cells and 1 tumor consisted predominantly of high-grade spindle cells. The neoplastic cells were arranged in solid sheets, nests, or intersecting fascicles. Mitotic activity ranged from 1 to 15/10 HPF (median: 5/10 HPF). Other features included rhabdoid phenotype (4/8), pronounced nuclear convolutions (2/8), prominent stromal hyalinization (2/8), focally myxoid stroma (1/8), foci of osteoclasts (1/8), and necrosis (1/8). By immunohistochemistry, all tumors showed diffuse and strong nuclear staining of NUT protein, with variable expression of pancytokeratin (AE1/AE3) (2/8), CK18 (1/8), CD99 (3/8), NKX2.2 (2/8), cyclin D1 (2/8), desmin (2/8), BCOR (2/8), S100 (1/8), TLE1 (1/8), and synaptophysin (1/8). Seven of 8 tumors demonstrated NUTM1 rearrangement by fluorescence in situ hybridization analysis. RNA-sequencing analysis identified MXD4::NUTM1 (3/7), MXI1::NUTM1 (3/7), and MGA::NUTM1 (1/7) fusions, respectively. DNA-based methylation profiling performed in 2 cases revealed distinct methylation cluster differing from those of NUT carcinoma and undifferentiated small round cell and spindle cell sarcomas. At follow-up (range: 4 to 24 mo), 1 patient experienced recurrence at 8.5 months, 4 patients were alive with metastatic disease (5, 10, 11, and 24 mo after diagnosis), 3 patients remained well with no signs of recurrence or metastasis (4, 6, and 12 mo after diagnosis). Our study further demonstrated that NUTM1 -rearranged sarcoma had a broad range of clinicopathologic spectrum. NUT immunohistochemistry should be included in the diagnostic approach of monotonous undifferentiated small round, epithelioid to high-grade spindle cell malignancies that difficult to classify by conventional means. DNA-based methylation profiling might provide a promising tool in the epigenetic classification of undifferentiated sarcomas.

Germline variants in patients diagnosed with pediatric soft tissue sarcoma.

BACKGROUND: While soft tissue sarcomas affect younger patients, few studies have assessed the distribution of underlying pathogenic germline variants. PATIENTS AND METHODS: We retrospectively identified all pediatric and young adult patients (0-22 years) at Haukeland University Hospital, Norway (1981-2019), through clinical and pathological records. We identified n = 46 eligible patients. From these 46 patients, adequate material representing normal tissue was available for n = 41 cases (n = 24 diagnosed with rhabdomyosarcoma, 9 with synovial sarcomas, 2 with Ewing sarcomas, and 6 without further classification), with matching tumor tissue for n = 40. Normal tissue samples were analyzed for germline pathogenic variants (PVs) by targeted sequencing of 360 cancer genes. RESULTS: Out of the 41 analyzed cases, we found PVs or likely PVs in 7 (17%). These variants were found in TP53, MUTYH, FANCC, DICER1, FANCA, MYO3A, and MYO5B. Supporting the causality of these PVs, four cases revealed loss of heterozygosity (LOH) of the wild-type allele in the tumor tissue, one patient with a PV in DICER1 had a second somatic variant in DICER1, and a patient with a PV in TP53 had the altered allele amplified in the tumor. For three out of five with available family history, a history of other cancers in relatives was recorded. Among genes with variants of uncertain significance, CHD1L was of particular interest, revealing a stop-gain and a missense variant. INTERPRETATION: A high fraction of young patients with soft tissue sarcoma harbor PVs. Among the genes affected, we substantiate a potential role of MYO5B and propose a potential role for MYO3A.

A Retrospective Analysis of Systemic Oncologic Treatment in Older Patients With Advanced Soft-tissue Sarcoma.

BACKGROUND/AIM: Almost half of all patients with soft-tissue sarcoma are over 65 years of age, and the proportion of older patients is increasing. Despite this, they have been underrepresented in clinical trials and only limited data are available to guide treatment decisions. The aim of this study was to investigate treatment patterns and outcomes in older patients with soft-tissue sarcoma. PATIENTS AND METHODS: Patients over 50 years old treated for advanced soft-tissue sarcoma at the Helsinki University Hospital between January 2000 and July 2020 were included. Data on patient and tumor characteristics, treatment, and survival were retrospectively collected. A total of 152 patients were included: 14.5% (n=22) were over 75 years old, 34.2% (n=52) were 65-74 and 51.3% (n=78) were 50-64 years old. RESULTS: The outcomes of the oldest group differed from those of younger patients; they were more likely to receive single-agent treatment as first-line therapy (90.9% vs. 28.8% and 24.4%, p<0.001) and had the lowest relative dose-intensity (70% vs. 88% and 95%, p<0.05). They experienced grade three to four hematological adverse events less frequently (38.1%, 56.9% and 72.7%, respectively, p=0.031), and received fewer lines of treatment (median of 1, 2 and 2, respectively, p=0.01). In patients aged ≥75 years, there was no association between further lines of therapy and improved survival. Compared to the youngest group, the oldest patients had a greater risk of dying (hazard ratio=1.7, 95% confidence interval=1.0-2.8, p=0.041) and their median overall survival was only 7.4 months, compared to 14.3 and 12.9 months in the two younger groups. CONCLUSION: These findings suggest that older patients tolerate chemotherapy when treatment is tailored to their needs but may not benefit as much as younger patients.

Mesna, Doxorubicin, Ifosfamide and Dacarbazine (MAID) Combination Chemotherapy for Retroperitoneal Sarcoma: A Single-center Experience.

BACKGROUND/AIM: There is limited evidence regarding the systemic treatment of retroperitoneal soft-tissue sarcoma, and the current Japanese guidelines fail to make definitive suggestions. Here, we report our experience with combination chemotherapy of mesna, doxorubicin, ifosfamide, and dacarbazine (MAID) in this population. PATIENTS AND METHODS: We retrospectively reviewed the records of eight patients (three male and five female) who received MAID for pathologically diagnosed metastatic unresectable retroperitoneal sarcoma (either leiomyosarcoma or pleomorphic sarcoma) between October 2019 and January 2022. Treatment efficacy, tolerability (need for dose reduction), and safety profiles were evaluated and summarized. RESULTS: At initiation, the median age was 56.0 years, and the body mass index was 20.0 kg/cm2 Six patients had Eastern Cooperative Oncology Group performance status scores of 0. The net clinical benefit was a partial response in three (37.5%) patients, stable disease in four (50.0%), and progressive disease in one (12.5%). During the median 90.8 weeks of follow-up, disease in five patients progressed, resulting in a median progression-free survival of 48.4 weeks, and five deaths occurred, resulting in an overall survival of 95.1 weeks. Commonly observed adverse events were neutropenia (eight patients), anemia (eight patients), and decreased platelet count (seven patients), which led to dose reduction (60-80%) in six patients. CONCLUSION: MAID combination therapy may be an acceptable option for advanced retroperitoneal sarcoma; however, its benefits must be carefully assessed owing to its not insignificant toxicity.

CIC::NUTM1 sarcomas occurred in soft tissues of upper limbs : a rare case report and literature review.

BACKGROUND: CIC-rearranged sarcomas (CRS) represent a new entity of undifferentiated small round cell sarcoma belonging to the Ewing-like sarcomas family. CRS are the most common type. Fusion partners for the CIC gene include DUX4, FOXO4, and the recently recognizedNUTM1. Rare cases of CIC::NUTM1 sarcoma in pediatric patients have recently been reported in brain, kidney, bone, and soft tissues. However, such cases have not been identified in the soft tissues of the limbs. CASE PRESENTATION: We reported a case of CIC::NUTM1 sarcoma located in the right upper limb of an 18-year-old man. The tumor displayed morphologic features typical of CIC::DUX4 sarcomas, with small- to medium-sized round cells, a lobular pattern, focal spindling, myxoid stroma, and patchy necrosis. The tumor diffusely expressed NUTM1, was positive for WT1cter at weak to moderate intensity, and was focally positive for CD99, while it was negative for keratins, EMA, P40, MyoD1, myogenin, NKX2.2, BCOR, and pan-TRK. Fluorescence in situ hybridization analyses revealed cleavage of the CIC and NUTM1 genes. CONCLUSION: CIC::NUTM1 sarcomas represent a novel molecular variant of CRS with a preference for the central nervous system and younger pediatric persons. Its morphology and phenotype may be mistaken for NUT carcinomas, and the behavior is more progressive than other forms of CRS. For this rare and newly discovered gene fusion variant, it is necessary to integrate molecular and immunohistochemical findings with morphologic features in the diagnosis of undifferentiated neoplasms.

Biological and therapeutic insights from animal modeling of fusion-driven pediatric soft tissue sarcomas.

Survival for children with cancer has primarily improved over the past decades due to refinements in surgery, radiation and chemotherapy. Although these general therapies are sometimes curative, the cancer often recurs, resulting in poor outcomes for patients. Fusion-driven pediatric soft tissue sarcomas are genetically defined by chromosomal translocations that create a chimeric oncogene. This distinctive, almost 'monogenic', genetic feature supports the generation of animal models to study the respective diseases in vivo. This Review focuses on a subset of fusion-driven pediatric soft tissue sarcomas that have transgenic animal tumor models, which includes fusion-positive and infantile rhabdomyosarcoma, synovial sarcoma, undifferentiated small round cell sarcoma, alveolar soft part sarcoma and clear cell sarcoma. Studies using the animal models of these sarcomas have highlighted that pediatric cancers require a specific cellular state or developmental stage to drive tumorigenesis, as the fusion oncogenes cause different outcomes depending on their lineage and timing of expression. Therefore, understanding these context-specific activities could identify targetable activities and mechanisms critical for tumorigenesis. Broadly, these cancers show dependencies on chromatin regulators to support oncogenic gene expression and co-opting of developmental pathways. Comparative analyses across lineages and tumor models will further provide biological and therapeutic insights to improve outcomes for these children.