Unclassified Sarcoma Research Articles

Left inguinal dedifferentiated liposarcoma and primary unclassified sarcoma of the left lung as synchronous multiple sarcomas: a case report

BackgroundPulmonary nodules in patients with soft tissue sarcomas are likely pulmonary metastases, whereas synchronous primary pulmonary sarcomas are rare. Without surgery, determining whether a solitary pulmonary nodule is a primary or metastatic nodule is difficult. Herein, we report a rare case of a primary pulmonary sarcoma that presented synchronously with a primary dedifferentiated liposarcoma.Case presentationA 77-year-old man presented to another hospital with left inguinal swelling and a suspected recurrent inguinal hernia. Computed tomography revealed a left inguinal mass and pure-solid nodule in the left lung and the patient was referred to our hospital for detailed examination and treatment. The inguinal mass was pathologically diagnosed as a dedifferentiated liposarcoma using needle biopsy, whereas bronchoscopic biopsy revealed histological findings suggestive of a sarcoma; however, the primary site could not be determined. Positron emission tomography–computed tomography revealed no high-accumulation lesions except for the two sarcomas. We decided to perform surgery on both sarcomas for diagnostic and curative purposes. The surgical specimens showed that the two sarcomas were different. Based on the immunohistochemical staining findings of MDM2, a left inguinal dedifferentiated liposarcoma and primary pulmonary unclassified sarcoma were diagnosed. The patient displayed no evidence of recurrence 1 year after surgery.ConclusionsWe encountered a rare case of synchronous multiple primary sarcomas, one presenting in the lung and the other in the soft tissue. Surgery was required to achieve a definitive diagnosis for the patient, who achieved disease-free survival at 1 year. This case suggests that proactive resection of pulmonary nodules in patients with soft tissue sarcomas may be feasible as a diagnostic treatment if complete resection is achieved.

Prevalence of neurotrophic tropomyosin receptor kinase (NTRK) fusion gene positivity in patients with solid tumors in Japan.

Members of the neurotrophic tropomyosin receptor kinase (NTRK) gene family, NTRK1, NTRK2, and NTRK3 encode TRK receptor tyrosine kinases. Intra- or inter-chromosomal gene rearrangements produce NTRK gene fusions encoding fusion proteins which are oncogenic drivers in various solid tumors. This study investigated the prevalence of NTRK fusion genes and identified fusion partners in Japanese patients with solid tumors recorded in the Center for Cancer Genomics and Advanced Therapeutics database of comprehensive genomic profiling test. In the analysis population (n = 46,621), NTRK fusion genes were detected in 91 patients (0.20%). The rate was higher in pediatric cases (<18 years; 1.69%) than in adults (0.16%). NTRK gene fusions were identified in 21 different solid tumor types involving 38 different partner genes including 22 (57.9%) previously unreported NTRK gene fusions. The highest frequency of NTRK gene fusions was head and neck cancer (1.31%) and thyroid cancer (1.31%), followed by soft tissue sarcoma (STS; 0.91%). A total of 97 NTRK fusion gene partners were analyzed involving mainly NTRK1 (49.5%) or NTRK3 (44.2%) gene fusions. The only fusion gene detected in head and neck cancer was ETV6::NTRK3 (n = 22); in STS, ETV6::NTRK3 (n = 7) and LMNA::NTRK1 (n = 5) were common. Statistically significant mutual exclusivity of NTRK fusions with alterations was confirmed in TP53, KRAS, and APC. NTRK gene fusion was detected from 11 STS cases: seven unclassified sarcoma, three sarcoma NOS, and one Ewing sarcoma. NTRK gene fusion identification in solid tumors enables accurate diagnosis and potential TRK inhibitor therapy.

Undifferentiated and Dedifferentiated Metastatic Melanomas Masquerading as Soft Tissue Sarcomas: Mutational Signature Analysis and Immunotherapy Response

The distinction between undifferentiated melanoma (UM) or dedifferentiated melanoma (DM) from undifferentiated or unclassifiable sarcoma can be difficult and requires the careful correlation of clinical, pathologic, and genomic findings. In this study, we examined the utility of mutational signatures to identify patients with UM/DM with particular attention as to whether this distinction matters for treatment because the survival of patients with metastatic melanoma has dramatically improved with immunologic therapy, whereas durable responses are less frequent in sarcomas. We identified 19 cases of UM/DM that were initially reported as unclassified or undifferentiated malignant neoplasm or sarcoma and submitted for targeted next-generation sequencing analysis. These cases were confirmed as UM/DM by harboring melanoma driver mutations, UV signature, and high tumor mutation burden. One case of DM showed melanoma in situ. Meanwhile, 18 cases represented metastatic UM/DM. Eleven patients had a prior history of melanoma. Thirteen of 19 (68%) of the tumors were immunohistochemically completely negative for 4 melanocytic markers (S100, SOX10, HMB45, and MELAN-A). All cases harbored a dominant UV signature. Frequent driver mutations involved BRAF (26%), NRAS (32%), and NF1 (42%). In contrast, the control cohort of undifferentiated pleomorphic sarcomas (UPS) of deep soft tissue exhibited a dominant aging signature in 46.6% (7/15) without evidence of UV signature. The median tumor mutation burden for DM/UM vs UPS was 31.5 vs 7.0 mutations/Mb (P < .001). A favorable response to immune checkpoint inhibitor therapy was observed in 66.6% (12/18) of patients with UM/DM. Eight patients exhibited a complete response and were alive with no evidence of disease at the last follow-up (median 45.5 months). Our findings support the usefulness of the UV signature in discriminating DM/UM vs UPS. Furthermore, we present evidence suggesting that patients with DM/UM and UV signatures can benefit from immune checkpoint inhibitor therapy.

Unclassified mesenchymal sarcoma with NTRK1-KHDRBS1 gene fusion: a case report of long-term tumor-free survival with crizotinib treatment

BackgroundMesenchymal sarcomas are tumors that originate from mesenchymal tissue. Most mesenchymal sarcomas can be accurately classified, but some are unclassifiable in clinical practice. Molecular detection methods enable patients to benefit from molecular-targeted therapies for many cancers, including lung, breast, and bowel cancers. Further, even unclassified tumors can have therapeutic targets. NTRK gene fusions are sporadic genetic alterations that occur across tumor entities. If NTRK gene fusions are detected, TRK inhibitors can be used regardless of the tumor entity.Case presentationThis report describes a case with an unclassifiable mesenchymal sarcoma carrying a neurotrophic tyrosine receptor kinase NTRK1-KHDRBS1 gene fusion that was diagnosed and treated at multiple hospitals. Diagnostic work-up included pathological and immunohistochemical analysis, which excluded angiosarcoma, dendritic cell sarcoma, and pseudomyogenic hemangioendothelioma. The patient achieved a long-term survival without tumor relapse after treatment with crizotinib.ConclusionsThis case will be of significant interest to pathologists because, despite the tumor being unclassified, a molecular target was identified. Although the FDA does not currently approve crizotinib for treatment of patients harboring NTRK gene fusions, this case provides new insights for diagnosis and treatment of mesenchymal sarcomas with NTRK1 gene translocations. Similar to ALKomas, which can be successfully treated using NTRK molecular-targeted therapy, tumors with NTRK gene translocations can be classified as NTRKomas, even when they occur at different organ sites, and with varying histological morphologies, and immunophenotypes.

Abstract 1181: Associations of socioeconomic status and race/ethnicity with metastasis at sarcoma diagnosis

Abstract Background: Sarcomas comprise a group rare and heterogeneous neoplasms. As sarcomas have few early recognizable signs, they often have an extended delay between symptom onset and diagnosis. Approximately 10% - 30% of sarcoma cases present with metastasis at diagnosis. However, the extent to which a delayed diagnosis increases the likelihood of presenting with metastasis remains unclear. To expand this under-researched area of study, we sought to determine whether socioeconomic status (SES) or race/ethnicity were independently associated with metastasis at diagnosis of sarcoma by individual subtype. Methods: The influence of small-area SES and race/ethnicity on metastasis at diagnosis of sarcoma across all ages was evaluated using data from the SEER program (years of diagnosis: 2001 – 2015). Small-area SES was evaluated from a composite index measured at the census-tract level. Odds ratios (OR) for presenting with metastasis and 95% confidence intervals (CI) were estimated from logistic regression models that included SES as an ordinal variable, race/ethnicity, age, sex and year of diagnosis. Analyses were stratified by age groups (pediatric; &amp;lt; 20 years, adult: 20 – 65 years, older adult: 65 + years) and reported for any subtype with more than 100 metastatic cases within each age group category. A secondary analysis of adult cases evaluated the influence of insurance status (uninsured, Medicaid insured, privately insured) on metastasis using logistic regression, adjusted for small-area SES, race/ethnicity, sex, age, and year; this analysis was restricted to the years of available data, 2007 – 2015. Results: A total of 55,635 first primary sarcoma cases were identified. A higher SES was associated with a lower odds of metastasis for pediatric osteosarcoma (ordinal OR: 0.90, 95% CI: 0.85, 0.99; p-trend: 0.02), liposarcoma in adults (ordinal OR: 0.85, 95% CI: 0.78, 0.94; p-trend: 0.001) and unclassified sarcomas in adults (ordinal OR: 0.91, 95% CI: 0.84, 0.98; p-trend: 0.01) and older adults (ordinal OR: 0.91, 95% CI: 0.83, 0.99; p-trend: 0.03); the odds of metastasis in the remaining subtypes evaluated were not associated with SES. We also observed the odds of metastasis to be higher in minority populations compared to non-Hispanic (NH)-white cases for several subtypes, including leiomyosarcoma in NH-black (OR: 1.80, 95% CI: 1.51, 2.14), Asian pacific islander and American Indian or Alaskan native (API/AIAN) (OR: 1.45, 95% CI: 1.17, 1.79), and Hispanic (OR: 1.32, 95% CI: 1.10, 1.57) adult cases, as well as Ewing sarcoma of soft tissue in Hispanic adult cases (OR: 1.81, 95% CI: 1.07, 1.34). Having Medicaid or no insurance was a strong predictor of presenting with metastasis for all subtypes evaluated, except Ewing sarcoma of bone (significant ORs ranged from 1.38 to 2.27), and attenuated the associations with SES. The increased odds of metastasis among NH-Black cases with leiomyosarcoma and unclassified sarcomas, however, remained statistically significant. (Leiomyosarcoma OR: 1.88, 95% CI: 1.52, 2.33; unclassified sarcomas OR: 1.62, 95% CI: 1.11, 2.35). Conclusion: Small-area SES was not associated with metastasis at diagnosis of most sarcomas. However, based on our analysis of insurance status, delayed access to care may still be an important predictor advanced stage. Biological factors may also play a role in the racial disparities for sarcoma stage observed in adults. Citation Format: Brandon J. Diessner, Logan G. Spector, Jenny N. Poynter. Associations of socioeconomic status and race/ethnicity with metastasis at sarcoma diagnosis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1181.

Associations of Socioeconomic Status, Public vs Private Insurance, and Race/Ethnicity With Metastatic Sarcoma at Diagnosis

Approximately 10% to 30% of patients with sarcoma present with detectable metastases at diagnosis. However, the extent to which presentation with metastases is due to delayed diagnosis vs other factors remains unclear. To evaluate whether socioeconomic status, insurance status, or race/ethnicity were associated with the presence of metastases at diagnosis of sarcoma. This cross-sectional study used data from the population-based Surveillance, Epidemiology, and End Results program. Adult and pediatric patients with an initial diagnosis of soft-tissue and bone sarcoma between 2001 and 2015 were stratified by age group (pediatric, <20 years; adult, 20-65 years; older adult, >65 years) and sarcoma subtype. Statistical analyses were performed between August 2019 and January 2020. Surveillance, Epidemiology, and End Results Census tract-level socioeconomic status index, insurance status, and race/ethnicity. The odds of presenting with metastases at diagnosis were calculated. A total of 47 337 patients with first primary malignant sarcoma were included (24 343 male patients [51.4%]), with 29 975 non-Hispanic White patients (63.3%), 5673 non-Hispanic Black patients (12.0%), 7504 Hispanic patients (15.8%), and 4185 American Indian-Alaskan Native and Asian Pacific Islander patients (8.8%). Liposarcoma in adults was the only subtype and age group combination that demonstrated a significant trend in incidence across socioeconomic status levels (odds ratio, 0.85; 99% CI, 0.76-0.96; P = .001). However, compared with having non-Medicaid insurance, having Medicaid or no insurance in adults was associated with an increased odds of metastases at diagnosis for 6 of the 8 sarcoma subtypes evaluated; osteosarcoma and Ewing sarcoma were the only 2 subtypes in adults for which metastases were not associated with insurance status. In addition, there was an increased risk of presenting with metastases among non-Hispanic Black adults diagnosed with leiomyosarcoma (odds ratio, 1.87; 99% CI, 1.41-2.48) and unclassified sarcomas (odds ratio, 1.65; 99% CI, 1.01-2.67) compared with non-Hispanic White adults that was independent of socioeconomic and insurance status. These findings suggest that delayed access to care is associated with advanced stage at diagnosis for several soft-tissue sarcoma subtypes in adults, whereas other factors may be associated with the metastatic progression of osteosarcoma and Ewing sarcoma, as well as the racial disparities observed with metastatic leiomyosarcoma and unclassified sarcomas.

Tag-n-trak study: Preliminary analysis of an unselected biobank tumors with NTRK fusion transcript, the French SFCE society contribution.

10540 Background: NTRK ( Neurotrophic receptor tyrosine kinase) fusion transcript was initially described in infantile fibrosarcoma (IFS) and is now known to be present in many other rare types of tumor with a lower incidence. The main objective of the study is to describe the presentation and outcome of unselected tumors with NTRK fusion transcript (NTRK-FTT) to better consider the role of TRK inhibitors (TRKi) in such entities. Methods: We selected patients (pts) from the Institut Curie biobank (adults and children) with NTRK-FTT and which were assessed by RT-qPCR then RNA sequencing in a prospective or retrospective process, between 2001 and 2019. Results: We identified 62 NTRK-FTT among 2119 screened tumors (2.2 cases/year with RT-qPCR and 6.9 cases/year with RNA seq after 2016), NTRK3 (44 cases) (including 41 NTRK3-ETV6), NTRK2 (9) or NTRK1 (9). Most of pts had under 2 years (y) (74%) and only 7 pts were adults. We report preliminary analysis of clinical observation for the first 27 pts. Median age was 0.4 y [0-60.2]. Pathologic diagnosis was IFS (12 cases), various CNS tumors (4), atypical teratoid rhabdoid tumor (1), myofibroblastic inflammatory tumor (2), benign tumors (3), cellular congenital mesoblastic nephroma (2), lipofibromatosis like neural tumor, myxoïd liposarcoma, unclassifiable sarcoma (1 each). Two pts had metastatic tumors. Among all, 22 had surgery (1 mutilating), 15 chemotherapy, 4 radiotherapy, and 5 received TRKi, as second line treatment (2 pts) or ≥ third line (3 pts). After a median follow-up of 50 months [range, 1-155], 20/27 pts remained in complete remission, 3 had stable residue, and 4 had progressive disease (associated to 1 disease-related and 1 toxic deaths). Five-year OS is 88% [95%CI, 73.5-100] and 5y-EFS 59.5% [95%CI, 41.7-84.9]. Conclusions: This descriptive study showed that NTRK-FTT is rare (2.9%), encompasses a variety of different histotypes (n = 14). Systematic RNA sequencing allowed to depict 3.5 times more NTRK-FTT than targeted RT-qPCR. Overall outcome is favorable despite frequent tumor events. According to tumor type and the uncertainties regarding the long-term side effects of TRKi, the benefit/risk ratio must be carefully evaluated before using these drugs in first line.

Prognostic role of % changes in longest tumor diameter (LTD) in localized high-risk soft tissue sarcoma (STS) treated with neoadjuvant chemotherapy in a randomized clinical trial.

11558 Background: We investigated the prognostic relevance of % change in LTD in patients (pts) with localized high-risk STS treated with neoadjuvant chemotherapy in a phase 3 randomized trial (NCT01710176), aimed at comparing 3 cycles of a neoadjuvant histology-tailored (HT) over 3 cycles of standard anthracycline + ifosfamide chemotherapy (S). Methods: Pts with localized high-risk STS of extremities or trunk wall, and a diagnosis of myxoid liposarcoma, leiomyosarcoma, synovial sarcoma, malignant peripheral nerve sheath tumors, undifferentiated pleomorphic sarcoma were randomly assigned to receive 3 cycles of S or HT. Pts affected by myxofibrosarcoma, pleomorphic liposarcoma, pleomorphic rhabomyosarcoma unclassified spindle cell sarcoma were prospectively registered and treated by S. Change of LTD was assessed comparing baseline dimension with that measured after 3 cycles of S or HT, before surgery. Only pts treated with neodjuvant chemotherapy alone were selected for the analysis. We first investigated Overall Survival (OS) from surgery of the groups identified by “any % reduction”, “no-change” or “increase” in LTD by Kaplan-Meier estimates and log-rank tests. Then we searched for cutoffs able to separate prognosis among pts with a LTD reduction applying the change-point method proposed by Contal - O’Quigley. Results: Of 325 pts who entered the study and evaluable for response, 181 received neoadjuvant chemotherapy alone (92 S and 89 HT group respectively) and were analyzed, while 144 received concurrent chemo-radiotherapy and were excluded. In the whole population, % changes in LTD were significantly associated (log rank p = 0.032) to OS. “Any % reduction in LTD (101/181pts) displayed a better prognosis compared to “no-change” (28/181 pts) or “any % increase” (52/181). The change-point analysis was applied to all, S and HT groups separately; a cutoff of = / &gt; 18.75% decrease in LTD was the optimal predictor of outcome for the S group (p = 0.031), while no size cut-off could be identified for the HT group. Conclusions: In our study, % change in LTD of pts treated with neoadjuvant chemotherapy for localized high-risk STS correlated with OS. However, a % decrease in LTD cut-off able to predict the best outcome could be identified only for pts treated in the S group, while no differences in outcome were found by any % LTD change in the HT group. Interestingly, the LTD cut-off identified in the S group was lower than the one selected to define a response by RECIST ( = / &gt; 18.75% decrease in LTD vs = / &gt; 30%). Clinical trial information: NCT01710176 .

The surgical management of sarcomas of the chest wall: A 13-year single institution experience

Chest wall sarcomas are rare. Resection and reconstruction pose significant anatomical and functional challenges. We present our experience of managing these tumours as plastic surgeons working within a specialist sarcoma MDT. All cases of chest wall sarcoma in which a plastic surgeon took part were analysed (2003-2016). Tumours of the breast, abdomen and groin were excluded. Demographics, surgical details and outcomes were analysed. Forty-seven patients were identified. Median age at presentation was 61 years (range 7-91). Thirty-three were male and 14 were female. Chondrosarcoma (n = 16) was the most frequently occurring tumour, followed by myxofibrosarcoma (n = 6), leiomyosarcoma (n = 5) and unclassified sarcomas (n = 5). The majority of tumours were of high (n = 16) or intermediate grade (n = 17) histologically. Wide local excision was carried out in all cases. Twenty-two cases required a mesh and cement reconstruction of the chest wall. Soft tissue reconstruction involved pedicled LD flap +-skin graft (n = 17), direct closure (n = 13), pedicled VRAM (n = 7), free ALT flap (n = 6), and others (n = 4). Clear resection margins were achieved in 32 patients (68%). Fourteen patients underwent adjuvant radiotherapy and four adjuvant chemotherapy. Nine patients (19%) developed a local recurrence, and the median duration from resection to recurrence was 17 months (range 3-72). Nine patients (19%) developed metastasis. Eleven patients died (23.4%), and the median duration of survival 30 months (range 3-92). Thirty-six patients remain well, with a median duration of follow up 57.5 months (range 6-141). Estimated 5 year disease specific survival is 74.2%. Plastic surgeons have a vital role in the management of chest wall sarcomas. We present a reconstructive algorithm, which has enabled us to achieve good oncological and functional outcomes and a low complication profile .

A case of unclassified sarcoma of the parotid gland

A case of unclassified sarcoma of the parotid gland

Significance of intraoperative radiation therapy and high cumulative radiation doses in retroperitoneal soft tissue sarcoma

IntroductionIn retroperitoneal soft tissue sarcoma (STS) local recurrence (LR) rates remain high despite more aggressive surgical approaches. Since wide resection margins cannot be achieved in all patients, application of intraoperative radiation therapy (IORT) has been frequently discussed. Still, the significance of IORT in multimodal treatment of retroperitoneal STS remains unclear. Material and methodsPatients undergoing resection of primary or recurrent retroperitoneal STS at the University of Heidelberg Department of General, Visceral and Transplantation Surgery were retrospectively analyzed. Univariate Kaplan-Meyer and multivariate Cox regression analyses were performed to identify predictors of LR-free survival and to investigate the impact of IORT and high cumulative radiation doses. Analyses with propensity-score matched subgroups for IORT and cumulative radiation dose were performed to control for selection bias. Subgroup analyses for patients with retroperitoneal liposarcoma were likewise performed. Results272 patients were identified. Recurrent tumors, histology of dedifferentiated liposarcoma or unclassified sarcoma and microscopically incomplete resection were associated with decreased LR-free survival. In liposarcoma, only recurrent and dedifferentiated tumors were confirmed as poor prognostic factors concerning LR. IORT and cumulative radiation doses exceeding 60 Gy did not influence LR rates (estimated 5-year LR-free survival: IORT: 39%, non-IORT: 46%; p = 0.79). ConclusionIn this retrospective evaluation, additional application of IORT does not significantly influence oncological outcome in retroperitoneal soft tissue sarcoma. Randomized trials are needed to clarify the benefit of IORT.

Expanding the Phenotypic Spectrum of Mesenchymal Tumors Harboring the EWSR1-CREM Fusion.

ATF1, CREB1, and CREM constitute the CREB family of transcription factors. The genes encoding these factors are involved in gene fusion events in human tumors. EWSR1-ATF1 and EWSR1-CREB1 are the 2 most characterized fusions, whereas EWSR1-CREM has been less studied. To better understand the phenotypic spectrum of mesenchymal tumors associated with the EWSR1-CREM fusion, we investigated archival cases using fluorescence in situ hybridization and/or RNA sequencing. Among 33 clear cell sarcomas of soft tissue tested, we found 1 specimen, a hand tumor bearing the rearrangements of EWSR1 and CREM, with classic histology and immunophenotype. None of 6 clear cell sarcoma-like tumors of the gastrointestinal tract tested harbored the EWSR1-CREM fusion. Among 11 angiomatoid fibrous histiocytomas, we found that 3 tumors of myxoid variant harbored the rearrangements of EWSR1 and CREM. All 3 tumors occurred in middle-aged men and involved the distal extremities (N=2) and the lung (N=1). Prominent lymphoid cuff, fibrous pseudocapsule, and amianthoid fiber were present in 3, 2, and 2 tumors, respectively, whereas none showed pseudoangiomatoid spaces. All 3 tumors were immunohistochemically positive for epithelial membrane antigen and desmin. These cases suggested a closer relationship between angiomatoid fibrous histiocytoma and a recently proposed novel group of myxoid tumors with CREB family fusions. Our cohort also included 2 unclassifiable sarcomas positive for EWSR1-CREM. One of these was an aggressive pediatric tumor of the abdominal cavity characterized by proliferation of swirling spindle cells immunopositive for cytokeratin and CD34. The other tumor derived from the chest wall of an adult and exhibited a MUC4-positive sclerosing epithelioid fibrosarcoma-like histology. Our study demonstrates that a wider phenotypic spectrum is associated with the EWSR1-CREM fusion than previously reported.

Characteristics of mismatch repair deficiency in sarcomas

Due to the efficacy of immune checkpoint inhibitor therapy in tumors with deficient mismatch repair, there has been a surge in demand for mismatch repair deficiency testing in various tumor types. Mismatch repair deficiency is not known to play a significant role in the pathogenesis of sarcomas, and the utility of testing these tumor types is not established. This study aimed to determine the frequency, pattern, and clinicopathologic correlates of mismatch repair deficiency in sarcomas. Three hundred and four sarcomas were profiled using a genomic platform that employs massively parallel sequencing to interrogate 447 cancer-associated genes. Mismatch repair status was evaluated by determining the number of small insertion/deletion events occurring in homopolymer regions per megabase of exonic sequence data across all genes. Molecular characteristics of mismatch repair-deficient sarcomas were compared to mismatch repair-deficient carcinomas (n = 70) also identified using the sequencing panel. Seven sarcomas (2.3%) were classified as mismatch repair-deficient: four unclassified sarcomas, and one each of pleomorphic rhabdomyosarcoma, epithelioid leiomyosarcoma and malignant PEComa. One patient had an established diagnosis of Lynch syndrome. In the remaining patients, the mismatch repair gene mutation was confirmed or suspected to be somatic. Mismatch repair immunohistochemistry confirmed the mismatch repair-deficiency status of all cases with alterations in the tested proteins. As expected, mismatch repair-deficient sarcomas showed a significantly elevated tumor mutation burden relative to mismatch repair-proficient sarcomas (median 16 versus 4.6, p < 0.001). However, in comparison to mismatch repair-deficient carcinomas, mismatch repair-deficient sarcomas showed a lower tumor mutation burden (median 28 versus 16, p = 0.006) and a significantly greater degree of chromosomal instability. Among mismatch repair-deficient sarcomas, PD-L1 was variably expressed on tumor-associated macrophages but not on tumor cells. Three patients received pembrolizumab: two progressed and one has stable disease with five months follow-up. Mismatch repair deficiency in histologically classifiable sarcomas is rare (1%) and is more common in unclassified sarcomas (10%). Additional study is required to determine the predictive role of mismatch repair-deficiency in sarcomas for immunotherapy.

ZEBRAS HAVE HOOVES TOO: A CASE OF THE PROSPECTIVE DIAGNOSIS OF A SMARCA4-DEFICIENT THORACIC SARCOMA IN A COMMUNITY HOSPITAL SETTING VIA INTERDISCIPLINARY AND INTERINSTITUTIONAL COLLABORATION

SESSION TITLE: Disorders of the Mediastinum 1 SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 pm - 02:15 pm INTRODUCTION: In 2015, Le Loarer and colleagues retrospectively investigated nineteen previously unclassified sarcomas and reported a new type of aggressive thoracic malignancy, a SMARCA4-deficient thoracic sarcoma (SMARCA4-DTS).[1] An additional 12 cases were described in 2017 by Yoshida et al, with similar clinical features, immunohistochemistry, and gene expression profiles.[2] SMARCA4-DTS are readily recognizable in clinical practice as poorly differentiated, bulky thoracic malignant tumors, in predominantly middle-aged male smokers, with undifferentiated rhomboid morphology and abundant mitotic figures. Median overall survival is 7– 24 months, with mortality often due to local progression and mediastinal compression.[1] CASE PRESENTATION: A 55-year-old male with a history of tobacco and IV drug abuse presented with a two months history of progressive dyspnea, 100 lb weight loss, and new onset atrial fibrillation. Mediastinal and hilar masses were identified on CT, with encasement of broncho-vascular structures and mass effect on the SVC and aortic arch. Preliminary pathology reported a poorly differentiated necrotic neoplasm suggestive of carcinoma with neuroendocrine features. [Table 1] Considering the high level of suspicion for a SMARCA4 deficient tumor, no established standard of care, and rapidly deteriorating hemodynamic and respiratory status, the patient was not a chemotherapy candidate. Unfortunately, on the day of final pathology confirmation[Table 2], the patient had progressive respiratory failure and despite aggressive resuscitative measures continued to decline. Comfort measures were initiated on hospital day 16. DISCUSSION: Differential diagnosis of SMARCA4-DTS is wide and distinction from carcinomas can be difficult, as it requires extensive genomic profiling and immunohistochemical workup. In our case, the keys to the prospective diagnosis included 1) prior awareness of SMARCA4 deficiency, 2) an early high level of suspicion, 3) in-person collaboration between oncology and pathology services, and 4) established collaboration between our community medical center and an institution capable of extensive genetic testing. Per further literature review, CD34 is a useful, commonly available marker, as it is expressed in most SMARCA4-DTS but is not usually in lung carcinomas.[1,2] SMARCA4, SMARCA2 and SOX2 testing is important for confirmation of diagnosis. Imaging findings may also be helpful, as SMARCA4-DTS frequently arises in mediastinum and pleura, rather than in the lung. CONCLUSIONS: SMARCA4-DTS can be identified based on their unique presentation, distinctive rhabdoid morphology and immunohistochemistry. Awareness and prospective diagnosis of this rapidly progressive and rare malignancy, may provide opportunities for improved clinical management, prognostication, and identification of therapeutic or palliative options.Acknowledgement: Charles J. Nicely, MD. Dr. David Klimstra, MD. Reference #1: Le Loarer F, Watson S, Pierron G, et al. SMARCA4 inactivation defines a group of undifferentiated thoracic malignancies transcriptionally related to BAF-deficient sarcomas. Nat Genet 2015;47:1200-5. Reference #2: Yoshida A, Kobayashi E,Kubo T, et al. Clinicopathological and molecular characterization of SMARCA4-deficient thoracic sarcomas with comparison to potentially related entities. Mod Pathol 2017;30: 797-809. DISCLOSURES: No relevant relationships by Aliaksandr Ramaniuk, source=Web Response

Molecular analysis of translocations associated with Ewing’s sarcoma in the differential diagnosis of undifferentiated and unclassified sarcomas

Molecular analysis of translocations associated with Ewing’s sarcoma in the differential diagnosis of undifferentiated and unclassified sarcomas

Histologic Appearance After Preoperative Radiation Therapy for Soft Tissue Sarcoma: Assessment of the European Organization for Research and Treatment of Cancer–Soft Tissue and Bone Sarcoma Group Response Score

Tocritically assess the prognostic value of the European Organization for Research and Treatment of Cancer-Soft Tissue and Bone Sarcoma Group (EORTC-STBSG) response score and define histologic appearance after preoperative radiation therapy (RT) for soft tissue sarcoma (STS). For a cohort of 100 patients with STS of the extremity/trunk treated at our institution with preoperative RT followed by resection, 2 expert sarcoma pathologists evaluated the resected specimens for percent residual viable cells, necrosis, hyalinization/fibrosis, and infarction. The EORTC response score and other predictors of recurrence-free survival (RFS) and overall survival (OS) were assessed by Kaplan-Meier and proportional hazard models. Median tumor size was 7.5cm; 92% were intermediate or high grade. Most common histologies were unclassified sarcoma (34%) and myxofibrosarcoma (25%). Median follow-up was 60months. The 5-year local recurrence rate was 5%, 5-year RFS was 68%, and 5-year OS was 75%. Distribution of cases according to EORTC response score tiers was as follows: no residual viable tumor for 9 cases (9% pathologic complete response); <1% viable tumor for 0, ≥1% to <10% for 9, ≥10% to <50% for 44, and ≥50% for 38. There was no association between EORTC-STBSG response score and RFS or OS. Conversely, hyalinization/fibrosis was a significant independent favorable predictor for RFS (hazard ratio 0.49, P=.007) and OS (hazard ratio 0.36, P=.02). Histologic evaluation after preoperative RT for STS showed a 9% pathologic complete response rate. The EORTC-STBSG response score and percent viable cells were not prognostic. Hyalinization/fibrosis was associated with favorable outcome, and if validated, may become a valid endpoint for neoadjuvant trials.

Survival impact of centralization and clinical guidelines for soft tissue sarcoma (A prospective and exhaustive population-based cohort).

PurposeThe outcome of sarcoma has been suggested in retrospective and non-exhaustive studies to be better through management by a multidisciplinary team of experts and adherence to clinical practice guidelines (CPGs). The aim of this prospective and exhaustive population based study was to confirm the impact of adherence to CPGs on survival in patients with localized sarcoma.Experimental designBetween 2005 and 2007, all evaluable adult patients with a newly diagnosis of localized sarcoma located in Rhone Alpes region (n = 634), including 472 cases of soft-tissue sarcoma (STS), were enrolled. The prognostic impact of adherence to CPGs on progression-free survival (PFS) and overall survival (OS) was assessed by multivariate Cox model in this cohort.ResultsThe median age was 61 years (range 16–92). The most common subtypes were liposarcoma (n = 133, 28%), unclassified sarcoma (n = 98, 20.7%) and leiomyosarcoma (n = 69, 14.6%). In the initial management phase, from diagnosis to adjuvant treatment, the adherence to CPGs for patients with localized STS was 36% overall, corresponding to 56%, 85%, 96% and 84% for initial surgery, radiation therapy, chemotherapy and follow-up, respectively. Adherence to CPGs for surgery was the strongest independent prognostic factor of PFS, along with age, gender, grade, and tumor size. For OS, multivariate analysis adherence to CPGs for surgery was a strong independent prognostic factor, with an important interaction with a management in the regional expert centers.ConclusionsThis study demonstrates impact of CPGs and treatment within an expert center on survival for STS patients in a whole population-based cohort.

Predictors of survival in patients with sarcoma admitted to the intensive care unit.

BackgroundAdvances in treatment of sarcoma patients has prolonged survival but has led to increased disease- or treatment-related complications resulting in greater number of admissions to the intensive care unit (ICU). Survival and long-term outcome information about such critically ill patients with sarcoma is unknown.MethodsThe primary objective of the study was to determine the ICU and post-ICU survival rates of critically ill sarcoma patients. Secondary objectives included determining the modifiable and non-modifiable predictors of poor survival. We performed a retrospective chart review of sarcoma patients admitted to the ICU at The University of Texas MD Anderson Cancer Center between January 1, 2005, and December 31, 2012. Main outcome measures were ICU mortality, in-hospital mortality and 1, 2, and 6-month survival rates. Covariates such as histological diagnosis, disease characteristics, chemotherapy use, Charlson comorbidity index, Sequential Organ Failure Assessment (SOFA) scores, and clinical findings leading to ICU admission were analyzed for their effects on survival.ResultsWe identified 172 admissions over the 8-year study period hat met our inclusion criteria. The study population was 45.9 % males with a median age of 52 years. The most common sarcoma subgroups were high-grade unclassified sarcoma (25 %) and bone tumors (17.4 %). The ICU mortality rate was 23.3 % (95 % confidence interval [CI], 16.9–29.6 %), and an additional 6.4 % of patients died before hospital discharge (95 % CI, 22.9–37.1 %). 6-month OS rates were 41 %. The median SOFA scores on admission were 6 (inter quartile range (IQR), 3.5–9) in ICU survivors and 10 (IQR, 6.5–14) in ICU non-survivors. Increase in SOFA scores ≥6 led to poor outcomes (ICU survival 13.3 %, OS 6.7 %). Charlson comorbidity index (HR 1.139, 95 % CI 1.023–1.268, p = 0.02) and discharge SOFA scores (HR 1.210, 95 % CI 1.141–1.283, p < 0.0001) correlated with overall survival.ConclusionsOur results suggest that patients that are admitted to the ICU for respiratory failure, cardiac arrest, septic shock, acute renal failure or acidosis and also have a high SOFA score with subsequent worsening in the ICU have poor prognosis. Based on the retrospective data which needs further validation we can recommend that judicious approach should be taken in patients with predictors of poor survival before subjecting them to aggressive treatment.

Primary intracranial soft tissue sarcomas in children, adolescents, and young adults: single institution experience and review of the literature

There is a paucity of literature reporting the outcome of intracranial sarcomas (IS) in children, adolescents, and young adults (CAYA). A multimodal therapeutic approach is commonly used, with no well-established treatment consensus. We conducted a retrospective review of CAYA with IS, treated at our institution, to determine their clinical findings, treatments, and outcomes. Immunohistochemistry (PDGFRA and EGFR) and DNA sequencing were performed on 5 tumor samples. A literature review of IS was also conducted. We reviewed 13 patients (median age, 7years) with a primary diagnosis of IS between 1990 and 2015. Diagnoses included unclassified sarcoma (n=9), chondrosarcoma (n=2), and rhabdomyosarcoma (n=2). Five patients underwent upfront gross total resection (GTR) of the tumor. The 5-drug regimen (vincristine, doxorubicin, cyclophosphamide, etoposide, and ifosfamide) was the most common treatment used. Nine patients died due to progression or recurrence (n=8) or secondary malignancy (n=1). The median follow-up period of the 4 surviving patients was 1.69years (range 1.44-5.17years). The 5-year progression-free survival and overall survival rates were 21 and 44%, respectively. BRAF, TP53, KRAS, KIT, ERBB2, MET, RET, ATM, and EGFR mutations were detected in 4 of the 5 tissue samples. All 5 samples were immunopositive for PDGFRA, and only 2 were positive for EGFR. IS remain a therapeutic challenge due to high progression and recurrence rates. Collaborative multi-institutional studies are warranted to delineate a treatment consensus and investigate tumor biology to improve the disease outcome.

SMARCA4 inactivation defines a group of undifferentiated thoracic malignancies transcriptionally related to BAF-deficient sarcomas

While investigating cohorts of unclassified sarcomas by RNA sequencing, we identified 19 cases with inactivation of SMARCA4, which encodes an ATPase subunit of BAF chromatin-remodeling complexes. Clinically, the cases were all strikingly similar, presenting as compressive mediastino-pulmonary masses in 30- to 35-year-old adults with a median survival time of 7 months. To help define the nosological relationships of these tumors, we compared their transcriptomic profiles with those of SMARCA4-mutated small-cell carcinomas of the ovary, hypercalcemic type (SCCOHTs), SMARCB1-inactivated malignant rhabdoid tumors (MRTs) and lung carcinomas (of which 10% display SMARCA4 mutations). Gene profiling analyses demonstrated that these tumors were distinct from lung carcinomas but related to MRTs and SCCOHTs. Transcriptome analyses, further validated by immunohistochemistry, highlighted strong expression of SOX2, a marker that supports the differential diagnosis of these tumors from SMARCA4-deficient lung carcinomas. The prospective recruitment of cases confirmed this new category of 'SMARCA4-deficient thoracic sarcomas' as readily recognizable in clinical practice, providing opportunities to tailor their therapeutic management.