Nakayama Shizuhide, Nishio Jun, Nagao Shunjiro, Aoki Mikiko, Nabeshima Kazuki, Yamamoto Takuaki
Department of Orthopaedic Surgery, Faculty of Medicine, Fukuoka University, Fukuoka, Japan.
Section of Orthopaedic Surgery, Department of Medicine, Fukuoka Dental College, Fukuoka, Japan.
Cancer Diagn Progn. 2022 Sep 3;2(5):592-597. doi: 10.21873/cdp.10147. eCollection 2022 Sep-Oct.
BACKGROUND/AIM: Angiofibroma of soft tissue (AFST) is a rare benign soft-tissue tumor that most frequently occurs in the lower extremities. It has a characteristic genetic feature with a balanced chromosomal translocation t(5;8)(p15;q13), resulting in a fusion of aryl hydrocarbon receptor repressor (AHRR) and nuclear receptor coactivator 2 (NCOA2).
A 55-year-old woman presented with a 2-year history of left knee pain and recently noticed the development of a palpable mass. Magnetic resonance imaging exhibited a well-defined intra-articular mass with iso-signal intensity relative to skeletal muscle on T1-weighted sequences, heterogeneous high signal intensity on T2-weighted sequences and avid, diffuse enhancement on contrast-enhanced fat-suppressed T1-weighted sequences. After an ultrasound-guided core needle biopsy, the lesion was successfully treated by arthroscopically-assisted complete excision. Histologically, the tumor was composed of uniform bland spindle cells in a myxoid to collagenous stroma with a prominent vascular network. Immunohistochemically, the spindle cells were diffusely positive for CD163 and CD68 and focally positive for estrogen receptor. Moreover, AHRR-NCOA2 fusion gene was detected by reverse transcription-polymerase chain reaction. There has been no clinical evidence of local recurrence at 1-year follow-up.
This is the first report of the detection of an AHRR-NCOA2 gene fusion associated with intra-articular AFST. AFST should be included in the extended differential diagnosis of an intra-articular soft-tissue mass, particularly if the mass is vascular.
背景/目的：软组织血管纤维瘤（AFST）是一种罕见的良性软组织肿瘤，最常发生于下肢。它具有特征性的基因特征，即染色体平衡易位t(5;8)(p15;q13)，导致芳烃受体阻遏物（AHRR）与核受体辅激活因子2（NCOA2）融合。
一名55岁女性，有2年左膝疼痛病史，近期发现可触及肿块。磁共振成像显示关节内有边界清晰的肿块，在T1加权序列上相对于骨骼肌呈等信号强度，在T2加权序列上呈不均匀高信号强度，在对比增强脂肪抑制T1加权序列上呈明显弥漫性强化。在超声引导下进行粗针活检后，通过关节镜辅助下完全切除成功治疗了该病变。组织学上，肿瘤由黏液样至胶原性基质中均匀的温和梭形细胞组成，伴有明显的血管网络。免疫组化显示，梭形细胞CD163和CD68弥漫性阳性，雌激素受体局灶性阳性。此外，通过逆转录-聚合酶链反应检测到AHRR-NCOA2融合基因。随访1年无局部复发的临床证据。
这是首例与关节内AFST相关的AHRR-NCOA2基因融合检测报告。AFST应纳入关节内软组织肿块的扩展鉴别诊断，特别是当肿块有血管时。
