表浅CD34阳性成纤维细胞瘤（SCD34FT）是一种罕见的间叶肿瘤。SCD34FT的遗传改变尚未确定。最近的研究表明它与PRDM10重排软组织肿瘤（PRDM10-STT）有重叠。本研究旨在利用荧光原位杂交（FISH）和靶向下一代测序（NGS）对10例SCD34FT进行表征。该研究招募了7名男性和3名女性，年龄在26至64岁之间。肿瘤位于大腿（8例）、足部和后背（各1例）的表浅软组织中，大小在1.5至7厘米之间。肿瘤由厚实的纺锤形至多边形细胞的片状和茎状组成，具有玻璃质质粒和多形核。有丝分裂活动缺失或低。常见和不常见的基质发现包括泡沫组织球浸润、黏液样变、外周淋巴样聚集、大型扩张血管、分枝毛细血管血管和血黄铁沉积。所有肿瘤表达CD34，其中4个表现出局灶细胞角蛋白免疫表达。在分析的9例中，FISH鉴定出7例（77.8%）的PRDM10重排。靶向NGS测试中4例中发现MED12 ::PRDM10融合。随访显示没有复发或转移。我们展示了SCD34FT中经常发生的PRDM10重排，并提供了与PRDM10-STT紧密相关的额外证据。©作者（们）2023。由牛津大学出版社代表美国临床病理学会出版。保留所有权利。有关权限，请发送电子邮件至：journals.permissions@oup.com。

Superficial CD34-positive fibroblastic tumor (SCD34FT) is a rare mesenchymal neoplasm. The genetic alterations of SCD34FT have yet to be determined. Recent studies suggest it overlaps with PRDM10-rearranged soft tissue tumor (PRDM10-STT).This study aimed to characterize a series of 10 cases of SCD34FT using fluorescence in situ hybridization (FISH) and targeted next-generation sequencing (NGS).The study recruited 7 men and 3 women aged between 26 and 64 years. The tumors were located in the superficial soft tissues of the thigh (8 cases), foot, and back (1 case each), ranging in size from 1.5 to 7 cm. The tumors were composed of sheets and fascicles of plump spindled to polygonal cells, with glassy cytoplasm and pleomorphic nuclei. Mitotic activity was absent or low. Common and uncommon stromal findings included foamy histiocytic infiltrates, myxoid changes, peripheral lymphoid aggregates, large ectatic vessels, arborizing capillary vasculature, and hemosiderin deposition. All tumors expressed CD34, and 4 demonstrated focal cytokeratin immunoexpression. In 7 of 9 (77.8%) cases analyzed, FISH identified PRDM10 rearrangement. Targeted NGS revealed a MED12::PRDM10 fusion in 4 of 7 cases tested. Follow-up showed no recurrence or metastasis.We demonstrate recurrent PRDM10 rearrangements in SCD34FT and provide additional evidence of a close relationship to PRDM10-STT.© The Author(s) 2023. Published by Oxford University Press on behalf of American Society for Clinical Pathology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.