[Angiofibroma of soft tissue: a clinicopathologic analysis of 24 cases].

Objective: To investigate the clinicopathologic and genetic features, pathologic diagnosis and differential diagnosis of angiofibroma of soft tissue(AFST). Methods: The clinicopathologic characteristics of 24 cases diagnosed at Fudan University Shanghai Cancer Center from 2011 to 2017 were analyzed; immunohistochemical staining and interphase fluorescence in situ hybridization (FISH) were performed, and the literatures were also reviewed. Results: There were 15 male and 9 female (male∶female=1.7∶1.0) patients with age of onset ranging from 8 to 68 years (mean, 45 years). Fourteen cases occurred in extremities, including upper limbs (n=3) and lower limbs (n=11); seven cases were in the trunk, and 1 case each was in the temporal region, retroperitoneum and liver, respectively. Clinically, the tumors usually presented as a slowly growing painless mass. Tumor sizes ranged from 0.8 to 14 cm (mean 4.6 cm). Microscopically, most lesions were well-circumscribed, with fibrous capsules. Few cases infiltrated the surrounding fibrofatty tissue focally. The tumors were mainly composed of sparse short spindle cells and numerous small, branching, thin-walled blood vessels distributed in amyxoid, fibromyxoid or collagenous matrix, often accompanied by medium-sized, round or irregular and ecstatic vessels at the tumor periphery.By immunohistochemistry, all tested cases expressed vimentin (5/5), and showed variable positivity for EMA (2/4), ER (1/2), PR (2/3), α-SMA (1/18)and desmin (1/10). Ki-67 proliferation index were all less than 5%. CD34, CD31 and ERG staining clearly outlined the contours of blood vessels in the stroma. Four cases were tested for NCOA2 gene rearrangement by FISH, of which three were positive. Follow-up data was available in 17 patients (range, 3 to 69 months; mean, 30 months) were all free of disease. Conclusions: Soft tissue angiofibroma is a benign fibroblastic neoplasm characterized by a prominent and complex vasculature set in a myxoid-to-collagenous stroma, and cytogenetically a distinctive NCOA2 gene rearrangement. Caution should be exercised for the possibility of potentially misinterpretation of AFST as vascular tumors and other myxoid soft tissue tumors.目的： 探讨软组织血管纤维瘤(AFST)的临床病理特点、分子遗传学特征、病理诊断和鉴别诊断。 方法： 回顾性复习复旦大学附属肿瘤医院2011至2017年24例AFST的临床病理学资料，行形态学观察、免疫组织化学染色和荧光原位杂交并复习相关文献。 结果： 24例患者，男性15例，女性9例(男∶女＝1.7∶1.0)。发病年龄8～68岁，平均年龄45岁。发生部位：四肢14例(上肢3例，下肢11例)，躯干7例，颞部、腹膜后和肝脏各1例。临床上多表现为缓慢生长的无痛性肿块，直径0.8～14.0 cm，平均4.6 cm。镜下观察：多数肿瘤境界清楚，有纤维性包膜，少数病例局部浸润邻近的纤维脂肪组织。肿瘤主要由稀疏分布的短梭形细胞和丰富的薄壁分支状血管组成，分布于黏液样、纤维黏液样或胶原性间质中。周边均可见圆形或不规则形扩张的中等大血管。免疫组织化学标记：短梭形细胞主要表达波形蛋白(5/5)，不同程度表达上皮细胞膜抗原(2/4)、雌激素受体(1/2)、孕激素受体(2/3)、α-平滑肌肌动蛋白(1/18)和结蛋白(1/10)，Ki-67阳性指数均小于5%。CD34、CD31和ERG清晰显示肿瘤内血管的轮廓和分布。4例行荧光原位杂交检测，其中3例存在NCOA2基因相关易位。17例获得随访资料，随访时间3～69个月(平均30个月)，均无瘤生存。 结论： AFST是一种良性纤维性肿瘤的新类型，以含有大量薄壁分支状小血管为特征，并显示特征性的NCOA2基因相关易位，需注意与血管性肿瘤及其他富含黏液样基质的软组织肿瘤相鉴别。.