Molecular Diagnosis of Ewing Sarcoma Family of Tumors

[Contributions and limitations of FISH analysis for the diagnosis of central nervous system tumors according to the 2021 WHO classification: Feedback from Sainte-Anne Hospital's Department of Neuropathology]

The fifth edition of the World Health Organization (WHO) Classification of Tumors of the Central Nervous System has identified many new tumor types and has established, for the first time, essential and desirable diagnostic criteria for each of them. Among these, genetic alterations play an important role associated with morphology. For the first time, epigenetic data can also constitute essential and/or desirable criteria. These genetic abnormalities can be fusions, deletions or gains/amplifications and can thus be detected by fluorescence in situ hybridization techniques. The purpose of this article is to present the advantages and limitations of this technique in reference to its specific use within neuro-oncopathology in light of the 2021 WHO classification.

Detection of various fusion genes by one-step RT-PCR and the association with clinicopathological features in 242 cases of soft tissue tumor

Introduction: Over the past decades, an increasing number of chromosomal translocations have been found in different STSs, which not only has value for clinical diagnosis but also suggests the pathogenesis of STS. Fusion genes can be detected by FISH, RT-PCR, and next-generation sequencing. One-step RT-PCR is a convenient method to detect fusion genes with higher sensitivity and lower cost. Method: In this study, 242 cases of soft tissue tumors were included, which were detected by one-step RT-PCR in multicenter with seven types of tumors: rhabdomyosarcoma (RMS), peripheral primitive neuroectodermal tumor (pPNET), synovial sarcoma (SS), myxoid liposarcomas (MLPS), alveolar soft part sarcoma (ASPS), dermatofibrosarcoma protuberans (DFSP), and soft tissue angiofibroma (AFST). 18 cases detected by one-step RT-PCR were further tested by FISH. One case with novel fusion gene detected by RNA-sequencing was further validated by one-step RT-PCR. Results: The total positive rate of fusion genes was 60% (133/213) in the 242 samples detected by one-step RT-PCR, in which 29 samples could not be evaluated because of poor RNA quality. The positive rate of PAX3-FOXO1 was 88.6% (31/35) in alveolar rhabdomyosarcoma, EWSR1-FLI1 was 63% (17/27) in pPNET, SYT-SSX was 95.4% in SS (62/65), ASPSCR1-TFE3 was 100% in ASPS (10/10), FUS-DDIT3 was 80% in MLPS (4/5), and COL1A1-PDGFB was 66.7% in DFSP (8/12). For clinicopathological parameters, fusion gene status was correlated with age and location in 213 cases. The PAX3-FOXO1 fusion gene status was correlated with lymph node metastasis and distant metastasis in RMS. Furthermore, RMS patients with positive PAX3-FOXO1 fusion gene had a significantly shorter overall survival time than those patients with the negative fusion gene. Among them, the FISH result of 18 cases was concordant with one-step RT-PCR. As detected as the most common fusion types of AHRR-NCOA2 in one case of AFST were detected as negative by one-step RT-PCR. RNA-sequencing was used to determine the fusion genes, and a novel fusion gene PTCH1-PLAG1 was found. Moreover, the fusion gene was confirmed by one-step RT-PCR. Conclusion: Our study indicates that one-step RT-PCR displays a reliable tool to detect fusion genes with the advantage of high accuracy and low cost. Moreover, it is a great tool to identify novel fusion genes. Overall, it provides useful information for molecular pathological diagnosis and improves the diagnosis rate of STSs.

Primary adrenal Ewing's sarcoma family of tumors with tumor thrombus of the inferior vena cava: a case report

BACKGROUND

Ewing's sarcoma is a malignant neoplasm that mainly occurs in skeletal tissue but can rarely arise in soft tissues. Recently, small round cell tumors (including Ewing's sarcoma) caused by chromosomal translocations have been collectively termed Ewing's sarcoma family of tumors. We report a rare case of primary adrenal Ewing's sarcoma family of tumors with tumor thrombus.

CASE PRESENTATION

A 22-year-old Asian woman was referred to our hospital with a left retroperitoneal tumor 19 cm in diameter. Tumor thrombus was identified from the left adrenal vein to the inferior vena cava, infiltrating the right atrium. Total tumor excision with left adrenalectomy, nephrectomy, and thrombectomy was performed under hypothermic circulatory arrest, followed by seven courses of adjuvant chemotherapy. The patient has shown no signs of recurrence as of 26 months postoperatively.

CONCLUSION

Radical surgery combined with systemic chemotherapy may contribute to good prognosis in patients with primary adrenal Ewing's sarcoma family of tumors.

The Efficacy of Molecular Analysis in the Diagnosis of Bone and Soft Tissue Sarcoma: A 15-Year Mono-Institutional Study

The histological diagnosis of sarcoma can be difficult as it sometimes requires the combination of morphological and immunophenotypic analyses with molecular tests. A total of 2705 tissue samples of sarcoma consecutively collected from 2006 until 2020 that had undergone molecular analysis were assessed to evaluate their diagnostic utility compared with histological assessments. A total of 3051 molecular analyses were performed, including 1484 gene fusions tested by c/qRT-PCR, 992 gene rearrangements analysed by FISH, 433 analyses of the gene status of MDM2, 126 mutational analyses and 16 NGS analysis. Of the samples analysed, 68% were from formalin-fixed, paraffin-embedded tissue and 32% were from frozen tissue. C/qRT-PCR and FISH analyses were conclusive on formalin-fixed, paraffin-embedded tissue in 74% and 76% of samples, respectively, but the combination of the two methods gave us conclusive results in 96% and 89% of frozen and formalin-fixed, paraffin-embedded tissues, respectively. We demonstrate the utility of c/qRT-PCR and FISH for sarcoma diagnosis and that each has advantages in specific contexts. We conclude that it is possible to accurately predict the sarcoma subtype using a panel of different subtype-specific FISH probes and c/qRT-PCR assays, thereby greatly facilitating the differential diagnosis of these tumours.

Molecular classification of soft tissue sarcomas for adequate diagnosis: A study on the northeast population of Morocco

Background

Soft tissue sarcomas (STS) are a heterogeneous group of tumors. For adequate therapeutic management, an accurate diagnosis is necessary. In Morocco, the diagnosis is essentially based on the morphological and immunohistochemical study. Compared to other techniques, fluorescence in situ hybridization (FISH) is easier to develop and less expensive. This study aims to assess the feasibility and utility of implementing FISH technique to improve diagnostic accuracy and establish a good classification.

Material and methods

This is a retrospective cohort study. 211 cases of mesenchymal tumors were included. Hematoxylin Eosin Safran (HES) staining was performed in all cases followed by immunohistochemistry (IHC). FISH was performed in all cases with suspected STS. The probes used were EWSR1, MDM2 and SS18. The performance of FISH and histopathological test were evaluated by the ROC curve method (receiver operating characteristic). We evaluated the concordance between FISH and real time PCR by Cohen test.

Results

The real-time PCR technique showed good agreement with the FISH test by a Kappa coefficient of 60% (p = 0.035). FISH was able to confirm that it is more accurate (Youden's Index = 91%) than histological/immunohistochemical analysis (Youden's Index = 51%), as well as the positive predictive value was higher (100%) with an ROC curve finding a larger area under the curve of 0.953 (95% CI: 0.918-0.988), p = 0.000 which supports that FISH shows high performance to present an accurate final diagnosis.

Conclusion

This is the first and the largest Moroccan series for the molecular diagnosis of STS by FISH. Our study shows that paraffin FISH is a sensitive and specific ancillary tool in the diagnosis of STS when used in the appropriate clinicopathological context.

Extraskeletal Ewing's Sarcoma with CD7 Positivity and T-cell Receptor/Immunoglobulin Rearrangement Masquerading as T-lymphoblastic Lymphoma

Background: Extraskeletal Ewing's Sarcoma (EES) may harbor more than one tumor-specific genetic abnormality, leading to diagnostic difficulties. Case report: We report a nine-year-old boy with recurrent mass of his right thigh. Tumor cells were round, with scant cytoplasm, finely dispersed chromatin, and inapparent, small nucleoli. The initial misdiagnosis was T-lymphoblastic lymphoma due to CD7 and TCR/Ig monoclonal rearrangement. As it expressed NKX2.2 and harbored an EWSR1-FLI1 fusion transcript, the diagnosis was changed to EES. The child underwent EES therapy with good initial response, but had a subcutaneous relapse at 22 months. Conclusion: In addition to typical genetic alterations, Ewing sarcoma can also express CD7 and TCR/Ig rearrangement, which are not limited to lymphoma.

SELNET clinical practice guidelines for bone sarcoma

Bone sarcoma are infrequent diseases, representing < 0.2% of all adult neoplasms. A multidisciplinary management within reference centers for sarcoma, with discussion of the diagnostic and therapeutic strategies within an expert multidisciplinary tumour board, is essential for these patients, given its heterogeneity and low frequency. This approach leads to an improvement in patient's outcome, as demonstrated in several studies. The Sarcoma European Latin-American Network (SELNET), aims to improve clinical outcome in sarcoma care, with a special focus in Latin-American countries. These Clinical Practice Guidelines (CPG) have been developed and agreed by a multidisciplinary expert group (including medical and radiation oncologist, surgical oncologist, orthopaedic surgeons, radiologist, pathologist, molecular biologist and representatives of patients advocacy groups) of the SELNET consortium, and are conceived to provide the standard approach to diagnosis, treatment and follow-up of bone sarcoma patients in the Latin-American context.

Clinicopathological and molecular study of 10 salivary gland clear cell carcinomas, with emphasis on rare cases with high grade transformation and occurring in uncommon sites

Background

As a rare salivary gland malignancy, clear cell carcinoma (CCC) is easily misdiagnosed. This study identified the features that allow better recognition of the clinicopathological and molecular characteristics and the prognosis of CCC, focusing on high-grade transformation (HGT) in this tumor and cases arising in uncommon sites.

Methods

Clinicopathological and follow-up data for 10 CCC samples were retrieved. Immunohistochemical (IHC) staining was performed, and fluorescence in situ hybridization (FISH) was used to detect EWSR1 gene rearrangements, EWSR1–ATF1 gene fusions, and MAML2 gene rearrangements.

Results

Histologically, typical CCCs comprised bland polygonal or round cells with clear cytoplasm. In contrast with typical CCCs, HGT tumor cells exhibited nuclear pleomorphism, high nuclear-to-cytoplasmic ratios, high mitotic activity, and necrosis. Rare morphologic features such as pseudopapillae, gland-like spaces, and entrapped ducts were also observed. Occasionally, tumors involving the oral cavity might arise from the overlying epithelium of the mucosal surface. Immunohistochemically, all the cases expressed p63, p40, and CK5/6, while myoepithelial-related markers were uniformly negative in all cases. HGT exhibited a wild type p53 expression pattern. FISH demonstrated EWSR1 rearrangement (10/10) and EWSR1–ATF1 fusion (4/5); however, MAML2 remained intact (0/3).

Conclusions

CCCs with HGT or occurring in uncommon sites are extremely rare. Combining morphology based IHC and molecular detection provided reliable evidence that the HGT component represented a transformation of CCC rather than the coexistence of another tumor and helped differentiating CCCs in uncommon sites from their mimics, avoiding potential misdiagnosis and inappropriate therapy. The overall prognosis for CCCs is good, except for the HGT cases, which needed continued treatment.

Sudden unexpected death in a 17-year-old boy due to unacknowledged adamantinoma-like Ewing sarcoma

A 17-year-old male with no previous medical history was admitted 2 days before his death to a local hospital after mild dyspnea. Electrocardiography, chest radiography, and blood analysis revealed no abnormalities. Blood oxygen saturation was 99%, and SARS-CoV-2 nasopharyngeal swabs tested negative; thus, he was discharged without prescriptions. After 2 days, the subject died suddenly during a pool party. Forensic autopsy was performed analyzing all anatomical districts. Cardiac causes were fully excluded after deep macroscopic and microscopic evaluation; lung and brain analyses showed no macroscopic pathology. Finally, a large subglottic solid mass was detected. The whitish neoplasm showed an aggressive invasion pattern to the thyroid and adjacent deep soft tissues and occluded the trachea. High-power microscopy showed sheets of small, uniform cells with scant cytoplasm; round nuclei; and small, punctate nucleoli, with immunohistochemical expression of CK8-18, AE1/AE3, and CD99. Using FISH analysis, the break-apart molecular probes (EWSR1 (22q12) Break - XL, Leica Biosystem, Nussloch, Germany) showed distinct broken red and green fluorochromes, diagnostic of Ewing sarcoma. The neoplasm was characterized as adamantinoma-like Ewing sarcoma, and the mechanism of death was identified as airway obstruction. The rarity of the case resides in the circumstances of death, which pointed to the possibility of sudden unexpected death due to heart disease, but an oncological cause and the underlying mechanism were finally diagnosed. The best method to perform autopsies is still complete, extensive, and systematic macroscopic sampling of organs and districts followed by histopathological analysis, in addition to immunohistochemical and molecular investigations in those cases in which they are necessary. In fact, when neoplasms are detected, the application of advanced techniques such as immunohistochemistry and molecular diagnostics is fundamental to accurately certify death.

Identification of a Novel FUS/ETV4 Fusion and Comparative Analysis with Other Ewing Sarcoma Fusion Proteins

Ewing sarcoma is a pediatric bone cancer defined by a chromosomal translocation fusing one of the FET family members to an ETS transcription factor. There have been seven reported chromosomal translocations, with the most recent reported over a decade ago. We now report a novel FET/ETS translocation involving FUS and ETV4 detected in a patient with Ewing sarcoma. Here, we characterized FUS/ETV4 by performing genomic localization and transcriptional regulatory studies on numerous FET/ETS fusions in a Ewing sarcoma cellular model. Through this comparative analysis, we demonstrate significant similarities across these fusions, and in doing so, validate FUS/ETV4 as a bona fide Ewing sarcoma translocation. This study presents the first genomic comparison of Ewing sarcoma-associated translocations and reveals that the FET/ETS fusions share highly similar, but not identical, genomic localization and transcriptional regulation patterns. These data strengthen the notion that FET/ETS fusions are key drivers of, and thus pathognomonic for, Ewing sarcoma. IMPLICATIONS: Identification and initial characterization of the novel Ewing sarcoma fusion, FUS/ETV4, expands the family of Ewing fusions and extends the diagnostic possibilities for this aggressive tumor of adolescents and young adults.

Penis as a primary site of an extraskeletal Ewing sarcoma: A case report

RATIONALE

The Ewing sarcoma family of malignant tumors is a group of tumors characterized by morphologically similar round-cell neoplasms and by the presence of a common chromosomal translocation; Ewing sarcoma family of tumors typically occur in children and young adults between 4 to 15 years of age. The primary tumor usually originates in the bone, extraskeletal localization is rare.

PATIENT CONCERN

We present a case report concerning a 32-year-old male patient with a primary involvement of the penis.

DIAGNOSIS

The histopathology from the first penile biopsy showed a small-cell neuroendocrine carcinoma; however, that result was based on a sample obtained at a different facility than the Sarcoma Center, where the investigating pathologist did not have the adequate expertise. The patient then underwent a radical penectomy and a second reading of the histology was demanded after a radical penile amputation when Ewing sarcoma with R1 resection was confirmed.

INTERVENTIONS

The patient was referred to the national Sarcoma Center, where - using a multidisciplinary approach - the treatment was started with curative intent. However, it was preceded by a non-standard initiation of the therapy due to the poor primary diagnosis.

OUTCOMES

The non-standard therapy at the onset of the disease caused a poor prognosis of an otherwise curable diagnosis. Despite all that, the patient survived for a relatively long time.

LESSONS

The treatment of sarcomas with atypical localizations should be conducted by an experienced multidisciplinary team in a center with experience in sarcoma treatment.

Primary round cell sarcomas of the urinary bladder with EWSR1 rearrangement: a multi-institutional study of thirteen cases with a review of the literature

Primary Ewing sarcoma (ES) of the urinary bladder is a rare and aggressive small blue round cell malignant neoplasm associated primarily with translocation involving EWSR1 and FLI1 genes located in the 22nd and 11th chromosomes, respectively. To date, 18 cases have been published in the literature as single-case reports, based chiefly on CD99 positivity (17 patients). Molecular confirmation by fluorescence in situ hybridization was performed in 9 patients, and FLI1 immunohistochemical (IHC) analysis was not performed in any of these published cases. Herein, we present thirteen patients of more comprehensive primary round cell sarcomas of the urinary bladder with EWSR1 rearrangement. Clinicopathologic parameters including demographics; clinical presentation; histopathologic, IHC, and molecular profiles; and management and follow-up data of 13 patients with primary round cell sarcomas with EWSR1 rearrangement (Ewing family of tumor) of the urinary bladder were analyzed. The studied patients (n = 13) included 6 females and 7 males; their age ranged from 4 years to 81 years (median = 30 years). The most common clinical presentation was hematuria (n = 7), followed by hydronephrosis (n = 2, one with renal failure). The tumor size ranged from 2.9 cm to 15 cm in maximum dimension. Conventional ES architecture and histology was observed in 6 cases, and diverse histology was observed in 7 cases (adamantinomatous pattern [n = 1], alveolar pattern [n = 1], ganglioneuroblastoma-like pattern [n = 2], and small cell carcinoma-like pattern [n = 3]). All the tumors were muscle invasive (invasion into the muscularis propria). IHC analysis showed that all tumors expressed FLI1, CD99, and at least one neuroendocrine marker. Focal cytokeratin staining was positive in 2 patients, and RB1 was retained in all patients. EWSR1 rearrangement was seen in 12 of 12 tumors (in 12 patients) tested. A combined multimodal approach that included surgery with chemotherapy was instituted in all patients. Follow-up was available for 11 patients (ranging from 5 to 24 months). Six patients either died of disease (n = 3) or other causes (n = 3). Five patients were alive with metastases to the liver (n = 1), liver and lung (n = 2), liver and abdominal wall (n = 1), and kidney (n = 1). Based on our experience with the largest series to date and aggregate of the published data, ES/round cell sarcomas with EWSR1 rearrangement occurring in the bladder have bimodal age distribution with poor prognosis despite aggressive therapy. Owing to its rarity and age distribution, the differential diagnosis is wide and requires a systematic approach for ruling out key age-dependent differential diagnoses aided with molecular confirmation.

An EWSR1-CREB3L1 Fusion Gene in Extraskeletal Undifferentiated Round Cell Sarcoma Expands the Spectrum of Genetic Landscape in the "Ewing-Like" Undifferentiated Round Cell Sarcomas

The molecular findings in Ewing sarcoma have greatly expanded in recent years. Furthermore, this is particularly true for the subset termed "Ewing-like" undifferentiated round cell sarcomas in which new translocations have been reported since the fourth edition of the WHO Classification of Tumours of Soft Tissue and Bone. Amid this expanding genetic landscape, we report a case of extraskeletal undifferentiated round cell "Ewing-like" sarcoma in a 27-year-old female. The patient presented with a large lung mass accompanied on staging imaging by deposits suspicious for metastatic disease in the humerus, calvarium, and lymph nodes of the neck and chest. Biopsy of the lung mass revealed a densely packed monotonous proliferation of round, uniform neoplastic cells with scant cytoplasm. By immunohistochemistry, the tumor cells were diffusely positive for CD99, synaptophysin, TLE1, EMA, and MUC4 and negative for FLI1, PAX7, AE1/3, S100, SOX10, WT1, p63, desmin, and HMB45. Fluorescence in situ hybridization demonstrated rearrangement of the EWSR1 gene. Next-generation sequencing based assay revealed an EWSR1-CREB3L1 fusion. Taken together, the histomorphologic and molecular findings were considered consistent with an undifferentiated round cell sarcoma with an EWSR1-CREB3L1 fusion. Although described in entities such as sclerosing epithelioid fibrosarcoma, low-grade fibromyxoid sarcoma, and small cell osteosarcoma, this has not been previously described in undifferentiated round cell ("Ewing-like") sarcoma. This finding adds to the growing list of undifferentiated round cell sarcomas with Ewing-like morphologic phenotype-associated fusion genes and may contribute to further defining and characterizing the different subset of tumors in the Ewing family of tumors.

High Specificity of BCL11B and GLG1 for EWSR1-FLI1 and EWSR1-ERG Positive Ewing Sarcoma

Ewing sarcoma (EwS) is an aggressive cancer displaying an undifferentiated small-round-cell histomorphology that can be easily confused with a broad spectrum of differential diagnoses. Using comparative transcriptomics and immunohistochemistry (IHC), we previously identified BCL11B and GLG1 as potential specific auxiliary IHC markers for EWSR1-FLI1-positive EwS. Herein, we aimed at validating the specificity of both markers in a far larger and independent cohort of EwS (including EWSR1-ERG-positive cases) and differential diagnoses. Furthermore, we evaluated their intra-tumoral expression heterogeneity. Thus, we stained tissue microarrays from 133 molecularly confirmed EwS cases and 320 samples from morphological mimics, as well as a series of patient-derived xenograft (PDX) models for BCL11B, GLG1, and CD99, and systematically assessed the immunoreactivity and optimal cut-offs for each marker. These analyses demonstrated that high BCL11B and/or GLG1 immunoreactivity in CD99-positive cases had a specificity of 97.5% and an accuracy of 87.4% for diagnosing EwS solely by IHC, and that the markers were expressed by EWSR1-ERG-positive EwS. Only little intra-tumoral heterogeneity in immunoreactivity was observed for differential diagnoses. These results indicate that BCL11B and GLG1 may help as specific auxiliary IHC markers in diagnosing EwS in conjunction with CD99, especially if confirmatory molecular diagnostics are not available.

Ewing Sarcoma With Emphasis on Extra-skeletal Ewing Sarcoma: A Decade's Experience From a Single Centre in India

INTRODUCTION

The diagnosis of Ewing sarcoma family of tumours (ESFT) is challenging, especially in adults and in extra-skeletal or visceral location. Several morphologic mimics with varied treatment options and prognosis confer diagnostic dilemmas. Application of ancillary diagnostic modalities in surgical pathology in clinical routine has enabled accurate diagnosis of ESFT in bone, soft tissues, and viscera.

AIM

The study aims to assess the clinicopathological features including molecular test results of ESFT with emphasis on sex, age, and location, especially extra-skeletal soft tissue and visceral location.

MATERIAL AND METHODS

Data of clinicopathological, molecular tests (wherever performed), diagnosis rendered in 302 ESFT over a decade from our centre were reviewed. Statistical comparison of skeletal and extra-skeletal tumours with reference to age and sex was done using SPSS package. The P value of <.05 was considered significant.

RESULTS

The cohort included 302 ESFTs with 49% skeletal and 51% extra-skeletal tumours. Thigh was most common site among skeletal tumours; chest wall, paraspinal location, and retroperitoneum among soft tissues (39.4%); and kidney, ovary, and cervix among visceral tumours (11.3%). Fluorescence in situ hybridisation for EWSR1 gene rearrangement was positive in 54 patients and reverse-transcriptase polymerase chain reaction in 19 patients. Predominance of male sex, younger age and location in extremities among skeletal tumours and lack of gender predilection, higher age and axial location in extra-skeletal tumours were noted, which were statistically significant. Molecular tests were performed more frequently in extra-skeletal tumours, especially in visceral tumours to establish the diagnosis.

CONCLUSIONS

The study showed statistically significant differences in the age, sex, and location between skeletal and extra-skeletal ESFT. The increased percentage of extra-skeletal tumours especially in viscera was attributed to the increased awareness and availability of ancillary techniques.

Spindle and Round Cell Sarcoma With EWSR1-PATZ1 Gene Fusion: A Sarcoma With Polyphenotypic Differentiation

The evolving classification of round cell sarcomas is driven by molecular alterations. EWSR1-PATZ1 fusion positive spindle and round cell sarcoma is one such new tumor entity. Herein, we report 2 EWSR1-PATZ1 fusion positive spindle and round cell sarcomas with overlapping histologic features and polyphenotypic differentiation. The intra-abdominal tumors affected female patients, 31-and 53-year old. Both tumors showed sheets and nests of round to spindle cells, fine chromatin, tiny conspicuous nucleoli, moderate cytoplasm, and thick bands of intratumoral fibrosis. On immunohistochemistry, both tumors showed positivity for CD99, desmin, myogenin, MyoD1, S100, Sox10, CD34, and GFAP and were negative for keratin. Fluorescence in situ hybridization revealed rearrangement at EWSR1 locus. Next-generation sequencing-based RNA fusion assay revealed EWSR1-PATZ1 fusion in both cases. EWSR1-PATZ1 fusion positive spindle and round cell sarcomas show abundant intratumoral fibrosis and polyphenotypic differentiation, thus mimicking a range of tumors including desmoplastic small round cell tumor. The precise classification of this spindle and round cell sarcoma and its relationship to the Ewing sarcoma family of tumors remains to be determined.

Bone Sarcoma WithEWSR1-NFATC2Fusion: Sarcoma With Varied Morphology and Amplification of Fusion Gene Distinct From Ewing Sarcoma

Ewing sarcomas are typified by EWSR1 fusion to ETS gene family members. Tumors with fusion partners other than ETS family members and atypical histologic features pose significant diagnostic challenges and controversies as to their classification. In this article, we report a tumor with EWSR1-NFATC2 fusion in the left femur of a 43-year-old man and with unusual morphologic features that resemble undifferentiated high-grade sarcoma. Analysis together with reported cases in the literature shows that tumors with EWSR1-NFATC2 exhibit distinctive clinicopathologic features, including predilection for young male adults, highly variable histology that varies from round cell tumors frequently associated with nuclear irregularity, short spindle cells with nuclear pleomorphism, to myoepithelial tumor-like with or without myxohyaline matrix. They show variable positivity to CD99, frequent expression of cytokeratins, and consistent high-level amplification of EWSR1-NFATC2 fusion gene with distinctive gene expression profile. These tumors thus deserve classification separate from Ewing sarcoma.

Association between TMPRSS2:ERG fusion gene and the prostate cancer: systematic review and meta-analysis

INTRODUCTION

To identify the association between the TMPRSS2:ERG fusion gene, their variants and the onset of localized prostate cancer.

MATERIAL AND METHODS

A systematic search strategy was carried out through MEDLINE, EMBASE, LILACS, CENTRAL and unpublished literature. We included randomized control trials, cohort, case-control and cross-sectional studies that involved patients >18 years-old assessing the association between TMPRSS2 fusion gene, its single nucleotide polymorphisms and prostate cancer. The primary outcome was prostate cancer defined by histology of the tumor coming from transrectal ultrasound guided biopsy, transurethral resection of the prostate or radical prostatectomy. We assessed the risk of bias with QUADAS2 and performed a meta-analysis with Stata 14.

RESULTS

We found 241 records with the search strategies. After duplicates were removed, 18 studies were included in qualitative analysis and 15 studies in meta-analysis. All included studies that had no applicability concerns and low risk of bias for flow and timing. Nine studies had an unclear risk of bias for index and reference tests, since they did not describe the blinding assessment appropriately. Regarding the association between TMPRSS2:ERG and prostate cancer, we found an odds ratio (OR) 2.24 and a 95% confidence interval (CI) (1.29 to 3.91). Regarding the kind of sample, urine showed an OR 2.79 and a 95% CI (1.12 to 6.98) and when using a DNA molecular template, the OR was 3.55 with a 95% CI (1.08 to 11.65).

CONCLUSIONS

There was an association between TMPRSS2:ERG fusion gene with the diagnosis of prostate cancer, mainly in urine samples and DNA-based molecular templates. TMPRSS2:ERG might be used as the gold standard biomarker for diagnosis and stratification of PCa.

Ewing sarcoma

Ewing sarcoma is the second most frequent bone tumour of childhood and adolescence that can also arise in soft tissue. Ewing sarcoma is a highly aggressive cancer, with a survival of 70-80% for patients with standard-risk and localized disease and ~30% for those with metastatic disease. Treatment comprises local surgery, radiotherapy and polychemotherapy, which are associated with acute and chronic adverse effects that may compromise quality of life in survivors. Histologically, Ewing sarcomas are composed of small round cells expressing high levels of CD99. Genetically, they are characterized by balanced chromosomal translocations in which a member of the FET gene family is fused with an ETS transcription factor, with the most common fusion being EWSR1-FLI1 (85% of cases). Ewing sarcoma breakpoint region 1 protein (EWSR1)-Friend leukaemia integration 1 transcription factor (FLI1) is a tumour-specific chimeric transcription factor (EWSR1-FLI1) with neomorphic effects that massively rewires the transcriptome. Additionally, EWSR1-FLI1 reprogrammes the epigenome by inducing de novo enhancers at GGAA microsatellites and by altering the state of gene regulatory elements, creating a unique epigenetic signature. Additional mutations at diagnosis are rare and mainly involve STAG2, TP53 and CDKN2A deletions. Emerging studies on the molecular mechanisms of Ewing sarcoma hold promise for improvements in early detection, disease monitoring, lower treatment-related toxicity, overall survival and quality of life.

Fluorescence in Situ Hybridization (FISH) for Differential Diagnosis of Soft Tissue Sarcomas

Introduction:

Soft tissue sarcomas are rare tumors comprising 1 percent of solid malignancies. The latest edition of WHO soft tissue pathology lists 94 benign and malignant soft tissue tumors. Many of these show a large degree of morphological overlap. Immunohistochemistry has been shown to be reliable in many cases for differential diagnosis of lesions, although cytogenetic tests are considered the gold standard for many entities.Fluorescence in-situ hybridization (FISH) is a cytogenetic technique that uses fluorescent probes that bind to only those parts of the chromosome which have a high degree of sequence complementarity. Many soft tissue tumors show recurrent genetic mutations that are now being used as diagnostic markers. Knowledge of the molecular identity allows prediction of behavior, prognosis and treatment response.

Objective:

The aim of this study was to identify genetic mutations in soft tissue sarcomas using FISH testing and to assess correlations with histological diagnosis.

Material and methods:

A total of 25 cases of different soft tissue sarcomas diagnosed on histology with the help of immunohistochemical staining and for which FISH studies were requested were included in this study. Three pathologists with a special interest in soft tissue sarcomas reviewed the cases. FISH tests for EWS, the X:18 translocation, FOXO1 and MDM2 were respectively applied for 8 cases of Ewing sarcoma, 8 cases of synovial sarcoma, 2 cases of rhabdomyosarcoma and 7 cases of dedifferentiated liposarcoma and atypical lipomatous tumors/well differentiated liposarcomas.

Results:

EWS gene fusion was detected in 7 out of 8 cases of Ewing sarcoma and the X: 18 translocation was positive in 3 of the 8 cases of synovial sarcoma. FOXO1 was not detected in either of the two rhabdomyosarcomas. MDM2 by FISH was detected in only one out of 5 cases of atypical lipomatous tumors and 1 out of 2 dedifferentiated liposarcomas.

Conclusion:

FISH is a useful adjunct in the diagnostic assessment of different types of soft tissue sarcomas. It is easy to set up, is relatively inexpensive and has the ability to diagnose sarcomas with great accuracy, especially in cases which can not be accurately classified even after thorough histological and immunohistochemical evaluation. It may play a very important role in the accurate diagnosis and correct management of patients.

[Avoiding pitfalls in the diagnostics of bone neoplasms from pathologists point of view : Importance of reference pathology]

Bone tumors account for only approximately 1 % of the total number of malignant tumors in humans so that they are only rarely diagnosed and appropriate experience is difficult to acquire. Although the number of entities is limited there exist very different clinical and radiological images depending on the manifestation in the different regions of the skeleton. Bone tumors are also histologically structured very differently even within a particular entity. Prior to the histopathological diagnosis the location of the lesion within the entire skeleton and in relation to the tumor-bearing bone must be clarified based on imaging findings, i.e. which bone is affected, which portion of the bone is affected and is the tumor centrally located in the marrow cavity, in the area of the corticalis or on the outside? It is known that bone tumors show diagnostically relevant preferential locations in both the total skeleton as well as within the affected bone depending on the entity and that the age of onset also varies. In this article the most common reasons for errors in assessment are discussed. In most cases it is possible for reference pathology to still correctly classify specific cases by a consistent consideration of diagnostic radiology in combination with morphology. Although diagnostic progress for specific entities of bone tumors has been achieved using molecular methods, the established principle of interdisciplinary cooperation is the prerequisite for the correct diagnosis of these tumors. The therapeutic consequences for patients can be substantial and result in life-long functional limitations depending on the diagnosis (e.g. joint resection for osteosarcoma in childhood and adolescence). A correct diagnosis is therefore of great importance for far-reaching therapeutic decision-making.

Ewing Sarcoma, an Update on Molecular Pathology with Therapeutic Implications

Ewing sarcoma is a developmental tumor characterized by balanced chromosomal translocations and formation of new fusion genes. Despite the large amount of knowledge regarding the molecular aspects obtained in the last few years, many questions still remain. This article focuses on research on the molecular pathology and possible developments in targeted therapies in this malignancy and discusses some related bottlenecks, as well as the possible role of pathologists, the availability of samples, the lack of appropriate animal models, and the resources needed to carry out preclinical and clinical research.

Robust diagnosis of Ewing sarcoma by immunohistochemical detection of super-enhancer-driven EWSR1-ETS targets

Ewing sarcoma is an undifferentiated small-round-cell sarcoma. Although molecular detection of pathognomonic EWSR1-ETS fusions such as EWSR1-FLI1 enables definitive diagnosis, substantial confusion can arise if molecular diagnostics are unavailable. Diagnosis based on the conventional immunohistochemical marker CD99 is unreliable due to its abundant expression in morphological mimics.

To identify novel diagnostic immunohistochemical markers for Ewing sarcoma, we performed comparative expression analyses in 768 tumors representing 21 entities including Ewing-like sarcomas, which confirmed that CIC-DUX4-, BCOR-CCNB3-, EWSR1-NFATc2-, and EWSR1-ETS-translocated sarcomas are distinct entities, and revealed that ATP1A1, BCL11B, and GLG1 constitute specific markers for Ewing sarcoma. Their high expression was validated by immunohistochemistry and proved to depend on EWSR1-FLI1-binding to highly active proximal super-enhancers. Automated cut-off-finding and combination-testing in a tissue-microarray comprising 174 samples demonstrated that detection of high BCL11B and/or GLG1 expression is sufficient to reach 96% specificity for Ewing sarcoma. While 88% of tested Ewing-like sarcomas displayed strong CD99-immunoreactivity, none displayed combined strong BCL11B- and GLG1-immunoreactivity.

Collectively, we show that ATP1A1, BCL11B, and GLG1 are EWSR1-FLI1 targets, of which BCL11B and GLG1 offer a fast, simple, and cost-efficient way to diagnose Ewing sarcoma by immunohistochemistry. These markers may significantly reduce the number of misdiagnosed patients, and thus improve patient care.

Primitive neuroectodermal tumour of the cervix: a rare diagnosis

A 48-year-old woman presented with symptoms of lower abdominal pain and vaginal discharge for 6 months. Clinical examination and pelvic ultrasound scan suggested a diagnosis of infected Gartner's cyst, for which she underwent vaginal cystectomy. However, histopathology and immunohistochemistry revealed a diagnosis of primitive neuroectodermal tumour of the cervix. Further investigations revealed the stage to be FIGO IIIB, which was inoperable. She received neoadjuvant chemotherapy (vincristine, adriamycin, cyclophosphamide alternating with ifosfamide, cisplatin and etoposide, every 21 days), but the tumour did not respond to treatment and she was started on radiotherapy with definitive intent (55.8 Gray in 31 fractions over 6.2 weeks). A PET-CT performed 2 months after completion of radiotherapy showed complete response, and she is now receiving adjuvant chemotherapy.

Establishment and Characterization of a Human Small Cell Osteosarcoma Cancer Stem Cell Line: A New Possible In Vitro Model for Discovering Small Cell Osteosarcoma Biology

Osteosarcoma (OSA) is the most common primary malignant bone tumor, usually arising in the long bones of children and young adults. There are different subtypes of OSA, among which we find the conventional OS (also called medullary or central osteosarcoma) which has a high grade of malignancy and an incidence of 80%. There are different subtypes of high grade OS like chondroblastic, fibroblastic, osteoblastic, telangiectatic, and the small cell osteosarcoma (SCO). In this study, for the first time, we have isolated, established, and characterized a cell line of cancer stem cells (CSCs) from a human SCO. First of all, we have established a primary finite cell line of SCO, from which we have isolated the CSCs by the sphere formation assay. We have proved their in vitro mesenchymal and embryonic stem phenotype. Additionally, we have showed their neoplastic phenotype, since the original tumor bulk is a high grade osteosarcoma. This research demonstrates the existence of CSCs also in human primary SCO and highlights the establishment of this particular stabilized cancer stem cell line. This will represent a first step into the study of the biology of these cells to discover new molecular targets molecules for new incisive therapeutic strategies against this highly aggressive OSA.

UK guidelines for the management of bone sarcomas

This document is an update of the British Sarcoma Group guidelines published in 2010. The aim is to provide a reference standard for the clinical care of patients in the UK with bone sarcomas. Recent recommendations by the European Society of Medical Oncology, The National Comprehensive Cancer Network and The National Institute for Health and Care Excellence have been incorporated, and the literature since 2010 reviewed. The standards represent a consensus amongst British Sarcoma Group members in 2015. It is acknowledged that these guidelines will need further updates as care evolves. The key recommendations are that bone pain or a palpable mass should always lead to further investigation and that patients with clinico-radiological findings suggestive of a primary bone tumour at any site in the skeleton should be referred to a specialist centre and managed by a fully accredited bone sarcoma multidisciplinary team. Treatment recommendations are provided for the major tumour types and for localised, metastatic and recurrent disease. Follow up schedules are suggested.

Defining Ewing and Ewing-like small round cell tumors (SRCT): The need for molecular techniques in their categorization and differential diagnosis. A study of 200 cases

BACKGROUND

Differentiation of Ewing sarcoma family of tumors (ESFT) and Ewing-like tumors remains problematic. Certain ESFT with morphological and immunohistochemical (IHC) profiles lack the EWSR1-ETS transcript. To improve diagnostic accuracy we investigated the presence of several specific transcripts in 200 small round cell tumors (SRCT) displaying ESFT morphology and immunophenotype in which EWSR1 FISH analysis was non-informative or negative.

DESIGN

200 tumors (formalin-fixed, paraffin-embedded) were analyzed by RT-PCR. All tumors were tested for EWSR1-ETS, EWSR1/WT1, PAX3/7-FOX01 or SYT/SSX transcripts, and the negative tumors were subsequently analyzed for CIC/DUX4, BCOR/CCNB3 and CIC/FOX04 transcripts.

RESULTS

133 (66.5%) ESFT displayed one of the above EWSR1-ETS translocations. Three cases (1.5%) revealed the SYT-SSX transcript for Synovial sarcoma, and one (0.5%) a EWSR1-WT1 transcript for Desmoplastic Small Round Cell tumor. The CIC-DUX4 translocation was found in six Ewing-like tumors (3%) with CD99 positivity. The BCOR-CCNB3 gene fusion was observed in 5 tumors (2.5%) displaying round or spindle cells with strong CCNB3 IHC expression in 3 tumors. Moreover, RT-PCR failed to detect any gene fusion transcripts in 19 tumors (9.5%) and were considered "undifferentiated small round cell sarcoma" (SRCS). Molecular biology results were non-informative in 33 SRCTs (16.5%) due to RNA degradation through inadequate fixation and/or decalcification.

CONCLUSION

Our analysis of 200 SRCTs confirms the molecular heterogeneity of neoplasms with ESFT morphology and highlight that molecular studies with RT-PCR including new emerging gene fusion transcripts are mandatory for the diagnosis when EWSR1 FISH is negative or non-informative. The incidence of CIC-DUX4, BCOR-CCNB3 and CIC-FOX04 transcripts was relatively low. A small group of Ewing-like sarcomas or undifferentiated SRCS remains unclassified. Adopting appropriate tissue fixation and processing protocols is important to avoid degradation of fixed/embedded tissue when no frozen tumor is available.

Primary paraesophageal Ewing's sarcoma: an uncommon case report and literature review

Ewing’s sarcoma is a rare and highly aggressive cancer most frequently arising in people under 20 years of age. We report an uncommon case of primary paraesophageal Ewing’s sarcoma in a 25-year-old male harboring the infrequent EWSR1/ERG fusion transcript with multiple splice variants coexisting in the same tumor. The patient was totally refractory to chemotherapy and died 17 months after diagnosis. We underscore the need for better understanding of the molecular pathogenesis of the disease and improved systemic therapy options.

[Avoiding pitfalls in the diagnostics of bone neoplasms: importance of reference pathology]

Bone tumors account for only approximately 1% of the total number of malignant tumors in humans so that they are only rarely diagnosed and appropriate experience is difficult to acquire. Although the number of entities is limited there exist very different clinical and radiological images depending on the manifestation in the different regions of the skeleton. Bone tumors are also histologically structured very differently even within a particular entity. Prior to the histopathological diagnosis the location of the lesion within the entire skeleton and in relation to the tumor-bearing bone must be clarified based on imaging findings, i.e. which bone is affected, which portion of the bone is affected and is the tumor centrally located in the marrow cavity, in the area of the corticalis or on the outside? It is known that bone tumors show diagnostically relevant preferential locations in both the total skeleton as well as within the affected bone depending on the entity and that the age of onset also varies. In this article the most common reasons for errors in assessment are discussed. In most cases it is possible for reference pathology to still correctly classify specific cases by a consistent consideration of diagnostic radiology in combination with morphology. Although diagnostic progress for specific entities of bone tumors has been achieved using molecular methods, the established principle of interdisciplinary cooperation is the prerequisite for the correct diagnosis of these tumors. The therapeutic consequences for patients can be substantial and result in life-long functional limitations depending on the diagnosis (e.g. joint resection for osteosarcoma in childhood and adolescence). A correct diagnosis is therefore of great importance for far-reaching therapeutic decision-making.

Models of biobanking and tissue preservation: RNA quality in archival samples in pathology laboratories and "in vivo biobanking" by tumor xenografts in nude mice-two models of quality assurance in pathology

Tissue banks represent essential resources and platforms for biomedical research serving basic, translational, and clinical research projects. In this article, we describe 2 models of biobanking and tissue preservation with different approaches and aims. Archive tissue biobanking is described here as a resource of residual pathology tissues for translational research, which represents the huge clinical heterogeneity. In this context, managing of tissues and RNA quality in archive tissue are discussed. The other model of tissue biobanking is referred to as xenograft tissue banking, which represents an alternative method for obtaining large amounts of tissue, over an indefinite period, in so far as the tumor can be transferred in vivo over generations, maintaining the histological and genetic particularities. A description of the method and examples of the application are given with particular emphasis on sarcomas (Ewing's sarcoma/primitive neuroectodermal sarcoma, synovial sarcomas, and rhabdomyosarcomas) and early stages of tumor angiogenesis in sarcomas.

ChildSeq-RNA: A next-generation sequencing-based diagnostic assay to identify known fusion transcripts in childhood sarcomas

Childhood sarcomas can be extremely difficult to accurately diagnose on the basis of morphological characteristics alone. Ancillary methods, such as RT-PCR or fluorescence in situ hybridization, to detect pathognomonic gene fusions can help to distinguish these tumors. Two major deficiencies of these assays are their inability to identify gene fusions at nucleotide resolution or to detect multiple gene fusions simultaneously. We developed a next-generation sequencing-based assay designated ChildSeq-RNA that uses the Ion Torrent platform to screen for EWSR1-FLI1 and EWSR1-ERG, PAX3-FOXO1 and PAX7-FOXO1, EWSR1-WT1, and ETV6-NTRK3 fusions of Ewing sarcoma (ES), alveolar rhabdomyosarcoma, desmoplastic small round cell tumor, and congenital fibrosarcoma, respectively. To rapidly analyze resulting data, we codeveloped a bioinformatics tool, termed ChildDecode, that operates on a scalable, cloud-computing platform. Total RNA from four ES cell lines plus 33 clinical samples representing ES, alveolar rhabdomyosarcoma, desmoplastic small round cell tumor, and congenital fibrosarcoma tumors was subjected to ChildSeq-RNA. This accurately identified corresponding gene fusions in each tumor type, with no examples of false positive fusion detection in this proof-of-concept study. Comparison with previous RT-PCR findings demonstrated high sensitivity (96.4%; 95% CI, 82.3%-99.4%) and specificity (100%; 95% CI, 56.6%-100%) of ChildSeq-RNA to detect gene fusions. Herein, we propose ChildSeq-RNA as a novel tool to detect gene fusions in childhood sarcomas at single-nucleotide resolution.

Molecular characterization and clinical impact of TMPRSS2-ERG rearrangement on prostate cancer: comparison between FISH and RT-PCR

Prostate cancer (PCa) is a very heterogeneous disease, and there are constraints in its current diagnosis. Serum PSA levels, digital rectal examination (DRE), and histopathologic analysis often drive to overdiagnosis and overtreatment. Since 2005, the presence of the genetic rearrangement between transmembrane-serine protease gene (TMPRSS2) and the erythroblast transformation-specific (ETS) member ERG (v-ets erythroblastosis virus E26 oncogene homolog avian) has been demonstrated in almost half of PCa cases. Both FISH and RT-PCR are useful tools for detecting these rearrangements, but very few comparatives between both techniques have been published. In this study, we included FFPE tumors from 294 PCa patients treated with radical prostatectomy with more than 5 years of followup. We constructed a total of 20 tissue microarrays in order to perform break-apart and tricolor probe FISH approaches that were compared with RT-PCR, showing a concordance of 80.6% (P < 0.001). The presence of TMPRSS2-ERG rearrangement was observed in 56.6% of cases. No association between TMPRSS2-ERG status and clinicopathological parameters nor biochemical progression and clinical progression free survival was found. In conclusion, this study demonstrates that both FISH and RT-PCR are useful tools in the assessment of the TMPRSS2-ERG fusion gene status in PCa patients and that this genetic feature per se lacks prognostic value.

Molecular diagnostics complementing morphology in superficial mesenchymal tumors

Molecular techniques are increasingly important in the practice of surgical pathology. In soft tissue tumors, there are a number of tumors with recurring cytogenetic abnormalities. Knowledge of these abnormalities has furthered our understanding of these tumors and has also allowed development of molecular techniques to aid in the diagnosis. This review will focus on mesenchymal tumors with specific cytogenetic abnormalities that may present as a superficial tumor of the dermis or subcutis.

High-grade sarcoma masquerading as growing teratoma syndrome after resection of ovarian immature teratoma: report of a case

SUMMARY

A thorough literature search revealed no previous reports of this entity, and we are the first to describe a case of a high-grade sarcoma arising from a recurrent immature teratoma misdiagnosed as growing teratoma syndrome. The patient was a 23-yr-old female, diagnosed at the age of 20 with a Stage IIIB immature ovarian teratoma. After surgery and chemotherapy, the patient developed multiple liver and pelvic masses that were diagnosed as mature teratomas based on small samples obtained by computed tomography-guided core biopsy. Three years after diagnosis the patient presented with severe respiratory difficulty and following resection, the final pathology revealed multiple tumors with foci of high grade sarcoma compatible with primitive neuroectodermal tumor/extraskeletal Ewing sarcoma based on morphology and immunohistochemistry (CD99, CD56). However, on the basis of further immunostaining and fluorescent in situ hybridization studies negative for rearrangement of EWSR1, the final pathologic diagnosis was high-grade unspecified (undifferentiated) sarcoma. This case illustrates the pitfalls of biopsying 1 site in a patient with recurrence of a heterogeneous tumor such as immature ovarian teratoma, especially when rendering a benign diagnosis such as growing teratoma syndrome. It is of utmost importance to adequately sample large-volume recurrent teratomas, and we suggest biopsying several different sites, to increase the likelihood of detecting a malignant component.