Intra-abdominal EWSR1/FUS-CREM-rearranged malignant epithelioid neoplasms: two cases of an emerging aggressive entity with emphasis on misleading immunophenotype

Agaimy A, Stöhr R, Otto M, Braesen JH, Pfarr N, Konukiewitz B, Kasajima A, Hartmann A, Kloeppel G (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Virchows Archiv Springer Verlag (Germany)

DOI: 10.1007/s00428-021-03140-3

Abstract

CREB family (CREB1, ATF1, and CREM) gene fusions are defining markers in diverse mesenchymal neoplasms (clear cell sarcoma, angiomatoid fibrous histiocytoma, and others). However, neoplasms harboring EWSR1-CREM/FUS-CREM fusions are rare and poorly characterized. We describe two cases (55-year-old male with 7.5 cm renal mass and 32-year-old female with 5.5 cm mesenteric mass) illustrating their misleading immunophenotypes. Histologically, both showed eosinophilic and focally clear epithelioid cells arranged into sheets, nests, and trabeculae. Immunohistochemistry showed ALK, EMA, and AE1/AE3 immunoreactivity suggesting ALK-rearranged renal cell carcinoma (Case 1) and coexpression of keratin, EMA, synaptophysin, and chromogranin-A, suggesting neuroendocrine neoplasm (Case 2). Targeted RNA sequencing revealed EWSR1-CREM (Case 1) and FUS-CREM (Case 2) fusions. These cases add to the spectrum of CREM fusion-positive intra-abdominal epithelioid neoplasms. Their unusual immunophenotype and unexpected sites represent major pitfalls, underline a wide differential diagnosis, and emphasize the value of molecular testing in correctly diagnosing them.

Authors with CRIS profile

Abbas Agaimy Lehrstuhl für Allgemeine Pathologie und Pathologische Anatomie Arndt Hartmann Lehrstuhl für Allgemeine Pathologie und Pathologische Anatomie

Involved external institutions

MVZ Medizinisches Versorgungszentrum für Histologie, Zytologie und Molekulare Diagnostik Trier DE Germany (DE) Medizinische Hochschule Hannover (MHH) / Hannover Medical School DE Germany (DE) Technische Universität München (TUM) DE Germany (DE)

How to cite

APA:

Agaimy, A., Stöhr, R., Otto, M., Braesen, J.H., Pfarr, N., Konukiewitz, B.,... Kloeppel, G. (2021). Intra-abdominal EWSR1/FUS-CREM-rearranged malignant epithelioid neoplasms: two cases of an emerging aggressive entity with emphasis on misleading immunophenotype. Virchows Archiv. https://doi.org/10.1007/s00428-021-03140-3

MLA:

Agaimy, Abbas, et al. "Intra-abdominal EWSR1/FUS-CREM-rearranged malignant epithelioid neoplasms: two cases of an emerging aggressive entity with emphasis on misleading immunophenotype." Virchows Archiv (2021).

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