Department of Pathology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan.
Division of Pathology, The Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan.
Histopathology. 2023 Jul;83(1):57-66. doi: 10.1111/his.14899. Epub 2023 Mar 20.
Angiofibroma of soft tissue (AFST) is a benign tumour characterised 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 tumours in the 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 a fibrohistiocytic nature of the tumour. 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 tumour 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 hybridisation in four resected cases with >10% desmin-positive tumour 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.
软组织血管纤维瘤（AFST）是一种良性肿瘤，其特征是病变中存在明显的树枝状血管。大约三分之二的 AFST 病例报告有 AHRR::NCOA2 融合，只有两例报告有其他基因融合：GTF2I::NCOA2 或 GAB1::ABL1。虽然 AFST 被纳入世界卫生组织 2020 年分类中的纤维母细胞和肌纤维母细胞瘤，但几乎所有检查的病例都报告组织细胞标记物，尤其是 CD163 阳性，这仍然表明肿瘤具有组织细胞性质的可能性。因此，我们旨在阐明 AFST 的遗传和病理谱，并确定组织细胞标记物阳性细胞是否为真正的肿瘤细胞。
我们评估了 12 例 AFST 病例，其中包括 10 例 AHRR::NCOA2 和 2 例 AHRR::NCOA3 融合。病理上，在两例病例中检测到核栅状排列，这在 AFST 中尚未报道。此外，一例通过额外广泛切除的肿瘤显示出严重的浸润性生长。免疫组织化学分析显示，在 9 例中有不同程度的结蛋白阳性细胞，而在所有 12 例中 CD163 和 CD68 阳性细胞均弥漫分布。我们还对 4 例有>10%结蛋白阳性肿瘤细胞的切除病例进行了双重免疫荧光染色和免疫荧光原位杂交。结果表明，在所有 4 例病例中，CD163 阳性细胞与 AHRR::NCOA2 融合的结蛋白阳性细胞不同。
我们的研究结果表明，AHRR::NCOA3 可能是第二常见的融合基因，而组织细胞标记物阳性细胞不是 AFST 中的真正肿瘤细胞。
