软组织血管纤维瘤（AFST）是一种良性肿瘤，其特征为病变中突出的分枝状血管。约三分之二的AFST病例被报道具有AHRR::NCOA2融合，只有两例报道具有其他基因融合：GTF2I::NCOA2或GAB1::ABL1。尽管AFST被包括在世界卫生组织2020年分类的成纤维细胞和肌成纤维细胞肿瘤中，但已报道几乎所有病例中组织球标记物，特别是CD163阳性，仍然存在肿瘤纤维组织细胞的可能性。因此，我们旨在澄清AFST的遗传和病理谱，并确定是否组织球标记物阳性的细胞是真正的肿瘤细胞。我们评估了12例AFST病例，其中包括10例AHRR::NCOA2和两例AHRR::NCOA3融合的病例。病理上，在两例中检测到未报道的核柱状。此外，额外宽切除的一例肿瘤显示了严重的浸润性生长。免疫组化分析表明，9例中存在不同程度的desmin阳性细胞，而12例中CD163-和CD68阳性细胞被广泛分布。我们还对4例具有>10％ desmin阳性肿瘤细胞的切除病例进行了双免疫荧光染色和免疫荧光原位杂交。结果表明，在所有四例病例中，CD163阳性细胞与AHRR::NCOA2融合的desmin阳性细胞不同。我们的发现表明，AHRR::NCOA3可能是第二常见的融合基因，AFST中组织球标记物阳性的细胞不是真正的肿瘤细胞。(241字)。本文受版权保护。保留所有权利。

Angiofibroma of soft tissue (AFST) is a benign tumor characterized by prominent arborizing blood vessels throughout the lesion. Approximately two-thirds of AFST cases were reported to have AHRR::NCOA2 fusion, and only two cases have been reported to have other gene fusions: GTF2I::NCOA2 or GAB1::ABL1. Although AFST is included in fibroblastic and myofibroblastic tumors in World Health Organization's 2020 classification, histiocytic markers, especially CD163, have been reported to be positive in almost all examined cases, and it still remains the possibility of fibrohistiocytic nature of the tumor. Therefore, we aimed to clarify the genetic and pathological spectrum of AFST and identify whether histiocytic marker-positive cells were true neoplastic cells.We evaluated 12 AFST cases, which included 10 cases with AHRR::NCOA2 and two with AHRR::NCOA3 fusions. Pathologically, nuclear palisading, which has not been reported in AFST, was detected in two cases. Furthermore, one tumor resected by additional wide resection revealed severe infiltrative growth. Immunohistochemical analysis indicated varying levels of desmin-positive cells in nine cases, whereas CD163- and CD68-positive cells were diffusely distributed in all 12 cases. We also performed double immunofluorescence staining and immunofluorescence in situ hybridization in four resected cases with >10% desmin-positive tumor cells. The results suggested that the CD163-positive cells differed from desmin-positive cells with AHRR::NCOA2 fusion in all four cases.Our findings suggested that AHRR::NCOA3 could be the second most frequent fusion gene, and histiocytic marker-positive cells are not genuine neoplastic cells in AFST. (241 words.).This article is protected by copyright. All rights reserved.