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Warmke LM, Strike SA, Fayad LM, Ahlawat S, Liu YJ, Mata DA, Rooper L, Baraban E, Zou YS, Gross JM. Undifferentiated Round Cell Sarcoma With CRTC1::SS18 Fusion: Expanding Clinicopathologic Features of a Rare Translocation Sarcoma With Prominent Desmoplastic Stroma. Mod Pathol 2024; 37:100555. [PMID: 38972355 DOI: 10.1016/j.modpat.2024.100555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/14/2024] [Accepted: 06/18/2024] [Indexed: 07/09/2024]
Abstract
Undifferentiated round cell sarcomas (URCS) represent a diverse group of tumors, including conventional Ewing sarcoma, round cell sarcoma with EWSR1/FUS-non-ETS fusions, CIC-rearranged sarcoma, and sarcoma with BCOR alterations. Since 2018, 3 cases of URCS with a novel CRTC1::SS18 gene fusion have been reported in the literature. Herein, we report 3 additional cases of CRTC1::SS18 sarcoma, thereby doubling the number of described cases and expanding the clinicopathologic features of this rare translocation sarcoma. Together with the previously reported cases, we show that the male-to-female ratio is 1:2 with a median age of 34 years (range, 12-42 years). Tumors occurred primarily in intramuscular locations involving the lower extremity. Histologically, all tumors contained uniform round-to-epithelioid cells with a moderate amount of eosinophilic cytoplasm growing in sheets and nests with prominent desmoplastic stroma reminiscent of desmoplastic small round cell tumor. Immunohistochemical results were nonspecific, demonstrating variable expression of CD99 (patchy), ALK, GATA3, and cyclin D1. RNA sequencing revealed CRTC1::SS18 gene fusions in all cases, involving exons 1 to 2 of CRTC1 (the 5' partner gene) on chromosome 19 and either exon 2 or exon 4 of SS18 (the 3' partner gene) on chromosome 18. The clinical course was variable. Although 1 previously reported case demonstrated aggressive behavior with a fatal outcome, 2 others had a relatively indolent course with gradual growth for 6 to 7 years prior to resection. Two cases developed metastatic disease, including 1 case with bilateral lung metastasis and 1 with locoregional spread to a lymph node. By analyzing the clinicopathologic features, we aimed to improve recognition of this rare translocation sarcoma to better understand its biologic potential, optimize patient management, and expand the current classification of URCS.
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Affiliation(s)
- Laura M Warmke
- Department of Pathology, Indiana University School of Medicine, Indianapolis, Indiana.
| | - Sophia A Strike
- Department of Orthopaedic Surgery, The Johns Hopkins Hospital, Baltimore, Maryland
| | - Laura M Fayad
- Department of Radiology and Radiological Science, The Johns Hopkins Hospital, Baltimore, Maryland
| | - Shivani Ahlawat
- Department of Radiology and Radiological Science, The Johns Hopkins Hospital, Baltimore, Maryland
| | - Yajuan J Liu
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington
| | | | - Lisa Rooper
- Department of Pathology, The Johns Hopkins Hospital, Baltimore, Maryland
| | - Ezra Baraban
- Department of Pathology, The Johns Hopkins Hospital, Baltimore, Maryland
| | - Ying S Zou
- Department of Pathology, The Johns Hopkins Hospital, Baltimore, Maryland
| | - John M Gross
- Department of Pathology, The Johns Hopkins Hospital, Baltimore, Maryland
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2
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Yoshida A. Ewing and Ewing-like sarcomas: A morphological guide through genetically-defined entities. Pathol Int 2023; 73:12-26. [PMID: 36484765 PMCID: PMC10107474 DOI: 10.1111/pin.13293] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 11/15/2022] [Indexed: 12/14/2022]
Abstract
The fifth edition of the World Health Organization classification of soft tissue and bone tumors redefined Ewing sarcoma by fusions between EWSR1/FUS and ETS family of transcription factors, and recognized three tumor groups among Ewing-like sarcoma: CIC-rearranged sarcoma, sarcoma with BCOR genetic alterations, and round cell sarcoma with EWSR1::non-ETS fusions. Although this classification underscores the critical role of molecular genetics in the diagnosis of small round cell sarcoma, each entry is recognized as a specific entity not only because they have different genetics but because their phenotypes are distinct and reasonably robust to support the diagnosis. This review focuses on the morphological aspects of Ewing sarcoma and a subset of Ewing-like sarcomas (CIC-rearranged sarcoma, BCOR-associated sarcoma, and EWSR1::NFATC2 sarcoma) for which phenotypic characteristics have been well established. Classic histological findings, uncommon variations, and recurrent diagnostic pitfalls are addressed, along with the utility of recently developed immunohistochemical markers (NKX2.2, PAX7, ETV4, BCOR, CCNB3, and NKX3.1). Phenotypic expertise would significantly expedite the diagnostic process and complement (or sometimes outperform) genetic testing, even in well-resourced settings. Morphological knowledge plays an even more substantial role in facilities that do not have easy access to molecular testing.
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Affiliation(s)
- Akihiko Yoshida
- Department of Diagnostic Pathology, National Cancer Center Hospital, Tokyo, Japan.,Rare Cancer Center, National Cancer Center, Tokyo, Japan
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Argani P, Matoso A, Gross JM, Zhang Y, SoRelle JA, Gagan J, Antonescu CR, Palsgrove D. Primary Renal Sarcoma with SS18::POU5F1 Gene Fusion. Genes Chromosomes Cancer 2022; 61:572-577. [PMID: 35521683 PMCID: PMC9271602 DOI: 10.1002/gcc.23053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 04/25/2022] [Accepted: 05/01/2022] [Indexed: 11/06/2022] Open
Abstract
We report the first case of a primary renal undifferentiated sarcoma harboring an SS18::POU5F1 gene fusion. The patient was a 38 year-old male diagnosed with a 5 cm renal tumor which invaded the adrenal gland and extended into the renal vein. Microscopically, the neoplasm had a predominantly undifferentiated round cell morphology, with areas of rhabdoid and spindle cell growth. Similar to the previously reported cases with this fusion, by immunohistochemistry the neoplasm expressed S100 protein and epithelial markers (diffuse EMA, focal cytokeratin), suggesting the possibility of a myoepithelial phenotype. This report documents another example of a fusion-positive undifferentiated soft tissue sarcoma occurring as a primary renal neoplasm, adding to the already broad list of such entities. It highlights the crucial role of molecular analysis in establishing a specific diagnosis given the overlapping morphology and immunophenotypes such entities may exhibit. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Pedram Argani
- Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD, USA.,Department of Oncology, The Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - Andres Matoso
- Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD, USA.,Department of Oncology, The Johns Hopkins Medical Institutions, Baltimore, MD, USA.,Department of Urology, The Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - John M Gross
- Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD, USA.,Department of Orthopedics, The Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - Yanming Zhang
- Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - Jeffrey A SoRelle
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Jeffrey Gagan
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX
| | | | - Doreen Palsgrove
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX
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Identification of novel SSX1 fusions in synovial sarcoma. Mod Pathol 2022; 35:228-239. [PMID: 34504309 DOI: 10.1038/s41379-021-00910-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 08/13/2021] [Accepted: 08/15/2021] [Indexed: 12/28/2022]
Abstract
Synovial sarcoma is characterized by variable epithelial differentiation and specific SS18-SSX gene fusions. The diagnosis is primarily based on phenotype, but fusion gene detection is increasingly being considered indispensable, with SS18 break-apart fluorescence in situ hybridization (FISH) being favored in many laboratories. However, SS18 FISH assay produces negative or atypical results in a minority of cases, leaving uncertainties in diagnosis and management. Here, we analyzed this challenging subset of SS18 FISH-negative/atypical synovial sarcoma using RNA sequencing and monoclonal antibodies that recognize SS18-SSX and the SSX C-terminus. Among 99 synovial sarcoma cases that were previously subjected to SS18 break-apart FISH, eight cases were reported as negative and three cases were indeterminate, owing to atypical signal patterns. Three of these 11 tumors (two monophasic and one biphasic) harbored novel EWSR1-SSX1 fusions, were negative for SS18-SSX staining, and were positive for SSX C-terminus staining. One monophasic tumor harbored a novel MN1-SSX1 fusion, and showed negative SS18-SSX expression and positive SSX C-terminus staining. Another monophasic tumor carried an SS18L1-SSX1 fusion, and was weakly positive for SS18-SSX, while SMARCB1 expression was reduced. The presence of these novel and/or rare fusions was confirmed using RT-PCR and Sanger sequencing. EWSR1-SSX1 was further validated by EWSR1 FISH assay. The remaining six tumors (five monophasic and one biphasic) showed strong SS18-SSX expression, and RNA sequencing successfully performed in three cases identified canonical SS18-SSX2 fusions. Based on a DNA methylation-based unsupervised clustering, the tumors with EWSR1-SSX1 and SS18L1-SSX1 clustered with synovial sarcoma, while the MN1-SSX1-positive tumor was not co-clustered despite classic histology and immunoprofile. In summary, we discovered novel and rare SSX1 fusions to non-SS18 genes in synovial sarcoma. The expanded genetic landscape carries significant diagnostic implications and advances our understanding of the oncogenic mechanism.
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Liu Z, Yuan H, Han M. Therapeutic Response of Soft Tissue Sarcoma With Novel SS18-POU5F1 Fusion: A Case Report. Front Oncol 2021; 11:666946. [PMID: 34249705 PMCID: PMC8263906 DOI: 10.3389/fonc.2021.666946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 06/07/2021] [Indexed: 11/20/2022] Open
Abstract
A novel SS18-POU5F1 fusion gene was recently reported in soft tissue sarcoma occurring in three adolescent and young adult patients. Herein, we firstly reported the treatment response of SS18-POU5F1 sarcoma to immune checkpoint inhibitor, angiogenesis inhibitor, chemotherapy and radiotherapy. Our patient demonstrated no response to various systemic therapies including immune checkpoint inhibitor, angiogenesis inhibitor and chemotherapy. However, we noted that the SS18-POU5F1 sarcoma had a quick, robust but transient clinical response to radiotherapy. Further studies are needed to elucidate the mechanism underlying the different tumor response to radiotherapy and systemic therapy in this kind of tumor.
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Affiliation(s)
- Zengjun Liu
- Tumor Research and Therapy Center, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.,Rare Tumors Department, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
| | - Hongtu Yuan
- Department of Pathology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
| | - Mingyong Han
- Tumor Research and Therapy Center, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
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Tay TKY, Sukma NB, Lim TH, Kuick CH, Goh JY, Chang KTE. Correlating SS18-SSX immunohistochemistry (IHC) with SS18 fluorescent in situ hybridization (FISH) in synovial sarcomas: a study of 36 cases. Virchows Arch 2021; 479:785-793. [PMID: 34091760 DOI: 10.1007/s00428-021-03135-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/30/2021] [Accepted: 06/01/2021] [Indexed: 12/27/2022]
Abstract
The recently introduced, highly sensitive and specific SS18-SSX immunohistochemistry (IHC) is an attractive alternative to SS18 fluorescence in situ hybridization (FISH) testing in synovial sarcoma (SS). However, little is known about how SS18-SSX IHC correlates with SS18 FISH. We correlated the SS18 FISH results of SS from 36 patients with SS18-SSX IHC. Twenty-six tumours had a classic break-apart FISH pattern (1 fused, 1 red and 1 green signal) and all stained positive for the IHC. Ten had an atypical (non-classic) FISH pattern of which 5 stained positive for the IHC. Four of these (including two with novel atypical SS18 FISH patterns) were confirmed to harbour the SS18-SSX fusion on targeted RNA sequencing, while one had classic features of a biphasic SS. The remaining 5 tumours stained negative for the IHC. One had a TPM3-NTRK1 fusion, and one had no fusion, while the remaining three had insufficient tissue/RNA for sequencing. The sensitivity of the IHC was 91% (after excluding the 2 cases with confirmed absence of SS18-SSX fusion). Twenty histologic mimics of SS also stained negative for the IHC (100% specificity). Our study shows that the SS18-SSX IHC is more specific than SS18 FISH in diagnosing SS, especially in cases with atypical FISH patterns. It correlates well with RNA sequencing result and has the potential to replace SS18 FISH testing. A positive IHC result supports the diagnosis of SS, while a tumour with atypical FISH pattern and negative IHC result should undergo further molecular testing.
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Affiliation(s)
- Timothy Kwang Yong Tay
- Department of Anatomical Pathology, Singapore General Hospital, 20 College Road, Academia, Diagnostic Tower Level 10, Singapore, 169856, Singapore. .,Department of Molecular Pathology, Singapore General Hospital, Singapore, Singapore.
| | - Nadiah Binte Sukma
- Department of Anatomical Pathology, Singapore General Hospital, 20 College Road, Academia, Diagnostic Tower Level 10, Singapore, 169856, Singapore
| | - Tse Hui Lim
- Department of Molecular Pathology, Singapore General Hospital, Singapore, Singapore
| | - Chik Hong Kuick
- Department of Pathology and Laboratory Medicine, KK Women's and Children's Hospital, Singapore, Singapore
| | - Jian Yuan Goh
- Department of Pathology and Laboratory Medicine, KK Women's and Children's Hospital, Singapore, Singapore
| | - Kenneth Tou En Chang
- Department of Pathology and Laboratory Medicine, KK Women's and Children's Hospital, Singapore, Singapore
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