METHODS: Radiological examination of a 41 years old woman showed an osteolytic lesion in the os pubis with a large soft tissue component. Examination of a core needle biopsy led to the diagnosis chondromyxoid fibroma, and the patient was treated with curettage. Microscopic examination of the specimen showed a tumor tissue in which a pink-bluish background matrix was studded with small spindled to stellate cells without atypia, fitting well the chondromyxoid fibroma diagnosis. Focally, a more cartilage-like appearance was observed with cells lying in lacunae and areas with calcification. G-banding analysis of short-term cultured tumor cells yielded the karyotype 46,XX,der(1)inv(1)(p33~34q42) add(1)(p32)?ins(1;?)(q42;?),del(5)(q31),der(5)t(1;5)(q42;q35)[12]/46,XX[3]. RT-PCR together with Sanger sequencing showed the presence of two IRF2BP2::CDX1 chimeric transcripts in which exon 1 of the IRF2BP2 reference sequence NM_182972.3 or NM_001077397.1 was fused to exon 2 of CDX1. Both chimeras were predicted to code for proteins containing the zinc finger domain of IRF2BP2 and homeobox domain of CDX1.
CONCLUSIONS: IRF2BP2::CDX1 chimera is recurrent in chondrogenic tumors. The data are still too sparse to conclude whether it is a hallmark of benign or malignant tumors.
方法:一名41岁女性的放射学检查显示耻骨溶骨性病变,软组织成分较大。检查核心针活检导致诊断软骨粘液样纤维瘤,患者接受了刮宫治疗。标本的显微镜检查显示肿瘤组织,其中粉红色的蓝色背景基质上布满了小的纺锤状星状细胞,没有异型性。很好地拟合软骨粘液样纤维瘤的诊断。集中,细胞位于腔隙和钙化区域,观察到更像软骨的外观。短期培养的肿瘤细胞的G显带分析产生了核型46,XX,der(1)inv(1)(p33〜34q42)加(1)(p32)?ins(1;?)(q42;?),del(5)(q31),der(5)t(1;5)(q42;q35)[12]/46,XX[3]。RT-PCR与Sanger测序一起显示存在两个IRF2BP2::CDX1嵌合转录物,其中IRF2BP2参考序列NM_182972.3或NM_001077397.1的外显子1与CDX1的外显子2融合。预测两种嵌合体编码含有IRF2BP2的锌指结构域和CDX1的同源盒结构域的蛋白质。
结论:IRF2BP2::CDX1嵌合体在软骨源性肿瘤中复发。数据仍然太稀疏,无法断定它是良性还是恶性肿瘤的标志。