Adamantinoma-like Ewing Sarcoma (ALES) May Harbor FUS Rearrangements : A Potential Diagnostic Pitfall

Palsgrove DN, Foss RD, Yu W, Garcia J, Rooper LM, Rekhtman N, Antonescu C, Gagan J, Agaimy A, Bishop JA (2023)

Publication Type: Journal article

Publication year: 2023

Journal

American Journal of Surgical Pathology Lippincott, Williams & Wilkins

Book Volume: 47

Pages Range: 1243-1251

Journal Issue: 11

DOI: 10.1097/PAS.0000000000002100

Abstract

Adamantinoma-like Ewing sarcoma (ALES) is a rare malignancy currently considered a variant of Ewing sarcoma with most known cases harboring EWSR1 rearrangements. Herein we present a series of 6 cases of EWSR1 -negative ALES. The tumors arose in the sinonasal tract (n=3), major salivary glands (submandibular gland=1; parotid=1), and anterior mediastinum (n=1) in patients ranging from 25 to 79 years of age. Most tumors were basaloid in appearance, growing in large nests separated by interlobular fibrosis without overt squamous pearls. However, 1 case closely resembled a well-differentiated neuroendocrine tumor with uniformly round nuclei, eosinophilic cytoplasm, and trabecular architecture. All cases were diffusely positive for pan-cytokeratin, p40 or p63, and CD99. A subset of cases showed diffuse reactivity for synaptophysin, including 1 sinonasal tumor which also demonstrated sustentacular S100 protein expression. Molecular testing showed FUS rearrangements in all cases. Gene partners included known ETS family members FEV (n=2) and FLI1 (n=1). Our results expand the molecular diagnostic considerations for ALES to include FUS rearrangements. We also show that ALES may harbor FUS :: FLI1 fusion, which has not been previously reported in the Ewing family of tumors. Furthermore, ALES may show unusual histologic and immunophenotypic features that can overlap with olfactory carcinoma including S100-positive sustentacular cells. ALES should be considered in the diagnostic differential of small round cell tumors and tumors with neuroendocrine differentiation with immunohistochemical workup to include p40 and CD99/NKX2.2.

Authors with CRIS profile

Abbas Agaimy Lehrstuhl für Allgemeine Pathologie und Pathologische Anatomie

Involved external institutions

University of Texas Southwestern Medical Center (UT Southwestern) US United States (USA) (US) University of Texas MD Anderson Cancer Center US United States (USA) (US) Mayo Clinic US United States (USA) (US) Johns Hopkins Hospital US United States (USA) (US) Memorial Sloan Kettering Cancer Center US United States (USA) (US)

How to cite

APA:

Palsgrove, D.N., Foss, R.D., Yu, W., Garcia, J., Rooper, L.M., Rekhtman, N.,... Bishop, J.A. (2023). Adamantinoma-like Ewing Sarcoma (ALES) May Harbor FUS Rearrangements : A Potential Diagnostic Pitfall. American Journal of Surgical Pathology, 47(11), 1243-1251. https://doi.org/10.1097/PAS.0000000000002100

MLA:

Palsgrove, Doreen N., et al. "Adamantinoma-like Ewing Sarcoma (ALES) May Harbor FUS Rearrangements : A Potential Diagnostic Pitfall." American Journal of Surgical Pathology 47.11 (2023): 1243-1251.

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