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Dehner CA, Torres-Mora J, Gupta S, Kipp BR, Halling KC, Chen S, Warmke LM, Michal M, Alani A, Yu W, Kovacs K, Obeidin F, Iwenofu OH, Satturwar S, Meis JM, Folpe AL. Sarcomas Harboring EWSR1::PATZ1 Fusions: A Clinicopathologic Study of 17 Cases. Mod Pathol 2024; 37:100400. [PMID: 38043789 DOI: 10.1016/j.modpat.2023.100400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 10/30/2023] [Accepted: 11/21/2023] [Indexed: 12/05/2023]
Abstract
Soft tissue sarcomas harboring EWSR1::PATZ1 are a recently recognized entity with variable morphology and a heterogeneous immunohistochemical profile. We studied 17 such tumors. The tumors occurred in 12 men and 5 women (median age, 50 years; range, 15-71 years), involved the thoracoabdominal soft tissues (14 cases; 82%), lower extremities (2 cases; 12%), and tongue (1 case; 6%), and ranged from 0.7 to 11.3 cm (median, 4.7 cm). All but 1 patient received complete surgical resection; 7 were also treated with neoadjuvant chemo/radiotherapy. All cases showed typical features of EWSR1::PATZ1 sarcoma, including uniform round to spindled cells, fibromyxoid matrix, fibrous bands, hyalinized vessels, and pseudoalveolar/microcystic spaces. Unusual features, seen in a subset of cases, included degenerative-appearing nuclear atypia, epithelioid cytomorphology, mature fat, abundant rhabdomyoblasts, high mitotic activity, and foci with increased cellularity and nuclear atypia. Positive immunohistochemical results were desmin (16/17, 94%), MyoD1 (13/14, 93%), myogenin (6/14, 43%), GFAP (10/10, 100%), S100 protein (15/17, 88%), SOX10 (7/13, 54%), keratin (10/17, 59%), CD99 (4/11, 36%), H3K27me3 (retained expression 9/9, 100%), p16 (absent expression 1/4, 25%), and p53 (wild type 3/3, 100%). Fusion events included EWSR1 exon 8::PATZ1 exon 1 (14/17, 82%), EWSR1 exon 9::PATZ1 exon 1 (2/17, 12%), and EWSR1 exon 7::PATZ1 exon 1 (1/17, 6%). No evaluated tumor had alterations of CDKN2A/B and/or TP53, or MDM2 amplification. Clinical follow-up (16 patients: median, 13.5 months; range, 1-77 months) showed distant metastases in 3 patients (1/3 at time of presentation) and no local recurrences. At the time of last follow-up, 14 patients were disease free, 1 was alive with disease, 1 was dead of disease (at 13 months), and 1 had an indeterminant pulmonary nodule. We conclude that the morphologic spectrum of EWSR1::PATZ1 is broader than has been previously appreciated. Although more long-term follow-up is needed, the prognosis of these very rare sarcomas may be more favorable than previously reported.
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Affiliation(s)
- Carina A Dehner
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota; Department of Pathology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Jorge Torres-Mora
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Sounak Gupta
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Benjamin R Kipp
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Kevin C Halling
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Shaoxiong Chen
- Department of Pathology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Laura M Warmke
- Department of Pathology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Michael Michal
- Department of Pathology, Faculty of Medicine in Plzen, Charles University, Plzen, Czech Republic; Biopticka Laboratory, Ltd, Plzen, Czech Republic
| | - Ali Alani
- Department of Pathology, Baylor University Medical Center, Dallas, Texas
| | - Wendong Yu
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Krisztian Kovacs
- Department of Pathology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Farres Obeidin
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Obiajulu Hans Iwenofu
- Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Swati Satturwar
- Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Jeanne M Meis
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Andrew L Folpe
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota.
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