Primary cutaneous Ewing sarcoma with diffuse S100/SOX10 positivity and pseudoalveolar pattern: An extraordinarily rare case highlighting a potential pitfall with significant repercussions

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Evangelou Z, Zhang L, Tafe LJ, Azzouz L, Grada Z, Linos K.

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J Cutan Pathol. 2021 Feb;48(2):302-308. doi: 10.1111/cup.13788. Epub 2020 Jul 27.

Abstract

Primary cutaneous Ewing sarcoma is a very rare entity with less than 100 cases reported in the literature, sharing the same morphological and immunohistochemical characteristics as their osseous counterparts. Herein, to the best of our knowledge, we report the first case in English literature of a molecularly confirmed Ewing sarcoma with diffuse and strong SOX10 immunoreactivity. This exceedingly rare immunohistochemical finding along with the rarity of this tumor could easily lead to a misdiagnosis with significant repercussions. Our case highlights the difficulty in diagnosing primary cutaneous Ewing sarcoma as well as the pivotal role molecular diagnostics can play in specific scenarios. CI – © 2020 John Wiley & Sons A/S . Published by John Wiley & Sons Ltd.

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Link/DOI: 10.1111/cup.13788