Mesenchymal/non-epithelial mimickers of neuroendocrine neoplasms with a focus on fusion gene-associated and SWI/SNF-deficient tumors

Kasajima A, Konukiewitz B, Schlitter AM, Weichert W, Braesen JH, Agaimy A, Kloeppel G (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Virchows Archiv Springer Verlag (Germany)

DOI: 10.1007/s00428-021-03156-9

Abstract

Mimickers of neuroendocrine neoplasms (NEN) include a number of important pitfall tumors. Here, we describe our experience with mesenchymal mimics of NENs to illustrate their spectrum and draw the attention particularly to a group of mesenchymal/non-epithelial neoplasms (MN) that combine epithelioid histology with neuroendocrine (NE-) features and peculiar genetic abnormalities. In a consultation series of 4498 cases collected between 2009 and 2021, 2099 neoplasms expressing synaptophysin and/or chromograninA were reviewed and analyzed. A total of 364 (18%) were diagnosed as non-NENs, while the remaining tumors were NEN. The group of mesenchymal/non-epithelial neoplasms with NE-features (MN-NE) included 31/364 (8%) cases. These mostly malignant neoplasms showed an epithelioid morphology. While all but one tumor expressed synaptophysin, mostly patchy, only 10/29 (34%) co-expressed chromograninA. A total of 13/31 (42%) of the MN-NE showed EWSR1-related gene fusions (6 Ewing sarcomas, 5 clear cell sarcomas, and 1 desmoplastic small round cell tumor, 1 neoplasm with FUS-CREM gene fusion) and 7 (23%) were SWI/SNF (SMARCB1 or SMARCA4)-deficient neoplasms. The remaining MN-NE included synovial sarcoma, sclerosing epithelioid mesenchymal neoplasm, melanoma, alveolar soft part sarcoma, solitary fibrous tumor, and chordoma. A total of 27/31 MN-NE were from the last 8 years, and 6 of them were located in the pancreas. Eleven MN-NE were initially diagnosed as neuroendocrine carcinomas (NECs). MN-NE with epithelioid features play an increasing role as mimickers of NECs. They mostly belong to tumors with gene fusions involving the EWSR1 gene, or with SWI/SNF complex deficiency. Synaptophysin expression is mostly patchy and chromograninA expression is infrequent in MN-NE of this series and data extracted from literature.

Authors with CRIS profile

Abbas Agaimy Lehrstuhl für Allgemeine Pathologie und Pathologische Anatomie

Involved external institutions

Technische Universität München (TUM) DE Germany (DE) Christian-Albrechts-Universität zu Kiel DE Germany (DE) Medizinische Hochschule Hannover (MHH) / Hannover Medical School DE Germany (DE)

How to cite

APA:

Kasajima, A., Konukiewitz, B., Schlitter, A.M., Weichert, W., Braesen, J.H., Agaimy, A., & Kloeppel, G. (2021). Mesenchymal/non-epithelial mimickers of neuroendocrine neoplasms with a focus on fusion gene-associated and SWI/SNF-deficient tumors. Virchows Archiv. https://doi.org/10.1007/s00428-021-03156-9

MLA:

Kasajima, Atsuko, et al. "Mesenchymal/non-epithelial mimickers of neuroendocrine neoplasms with a focus on fusion gene-associated and SWI/SNF-deficient tumors." Virchows Archiv (2021).

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