CBFA2T3::GLIS2融合的急性髓系白血病最初可表现为髓外病变（髓系肉瘤），导致误诊为非血液学儿童实体瘤。我们对4例CBFA2T3::GLIS2融合阳性儿童髓系肉瘤的临床病理特征进行了分析肉瘤要么没有白血病受累（孤立性骨髓肉瘤；3/4 [75%]），要么并发白血病（1/4 [25%]）的患者。所有病例在形态学和免疫表型水平上都模仿非造血肿瘤，因此初步评估并未引起对急性髓系白血病/髓系肉瘤的怀疑。然而，经过广泛的检查，包括分子研究，诊断为 CBFA2T3::GLIS2 融合的骨髓肉瘤。这项研究强调了在儿童小圆细胞肿瘤的鉴别诊断中需要对 GLIS2 重排的骨髓肉瘤高度怀疑指数组织活检和应用充分的检查以避免误诊该实体。© 作者 2024。由牛津大学出版社代表美国临床病理学会出版。版权所有。如需商业重复使用，请联系 reprints@oup.com 获取转载和转载的翻译权。所有其他权限都可以通过我们网站文章页面上的权限链接通过我们的 RightsLink 服务获得 - 如需更多信息，请联系journals.permissions@oup.com。

Acute myeloid leukemia with CBFA2T3::GLIS2 fusion can initially present as extramedullary lesions (myeloid sarcoma), leading to a misdiagnosis of nonhematologic pediatric solid tumors.We characterized the clinicopathologic features of 4 cases of CBFA2T3::GLIS2 fusion-positive myeloid sarcoma in pediatric patients where the sarcoma presented either without leukemic involvement (isolated myeloid sarcoma; 3/4 [75%]) or had concurrent leukemic disease (1/4 [25%]).All cases mimicked nonhematopoietic tumors at morphologic and immunophenotypic levels, so the initial evaluation did not raise suspicion for acute myeloid leukemia/myeloid sarcoma. After extensive workup, however, including molecular studies, the diagnosis of myeloid sarcoma with CBFA2T3::GLIS2 fusion was rendered.This study highlights the need for a high suspicion index of GLIS2-rearranged myeloid sarcoma in the differential diagnosis of pediatric small round cell tumors in tissue biopsies and the application of adequate workup to avoid misdiagnosing this entity.© The Author(s) 2024. Published by Oxford University Press on behalf of American Society for Clinical Pathology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.