TFCP2重排横纹肌肉瘤的临床病理学特征

Clinicopathological features of TFCP2-rearranged rhabdomyosarcoma

目的探讨TFCP2重排横纹肌肉瘤(RMS)的临床病理特点、分子遗传学特征和生物学行为。方法收集复旦大学附属肿瘤医院病理科2020年诊断的1例TFCP2重排RMS的临床病理资料,行免疫组化染色、荧光原位杂交(FISH)和二代测序(NGS),并复习相关文献。结果患者男性,37岁;因“右胸壁肿瘤两次术后复发”就诊。体格检查:右胸壁可触及直径约4 cm肿块,边界欠清,质地中等,活动度差。大体检查:肿瘤位于骨骼肌内,边界较清晰,切面灰白灰红,半透明,质韧。镜下形态:肿瘤边界相对清楚,局灶浸润骨骼肌;肿瘤主要由条束状或交叉束状排列、相对一致的梭形细胞组成,瘤细胞轻-中度异型,可见核分裂象;部分区域见散在炎症细胞浸润及淋巴滤泡形成,类似炎性肌纤维母细胞肿瘤。瘤细胞除表达Desmin、myogenin和MyoD1外,并弥漫强表达ALK,局灶表达AE1/AE3。FISH检测显示FUS基因易位,无ALK基因易位;NGS检测显示TFCP2-FUS融合。结论TFCP2重排RMS是一种具有独特临床病理特征的RMS新亚型,多见于青年人,好发于骨,尤其是颅面骨,多呈混合性梭形和上皮样细胞形态,且共表达横纹肌、上皮标记和ALK,具有高度侵袭性,预后差。

Objective To investigate the clinicopathological characteristics,molecular features and clinical behaviors of TFCP2-rearranged rhabdomyosarcoma(RMS).Methods One case of TFCP2-rearranged RMS diagnosed in the Department of Pathology,Fudan University Shanghai Cancer Center in 2020 was collected.Immunohistochemical staining,fluorescence in-situ hybridization and next-generation sequencing were performed,and literatures were reviewed.ResultsThe patient was a 37-year-old man who presented with a recurrent tumor on the right chest wall.On physical examination,a palpable mass with a poorly defined boundary and medium texture was found on the right chest wall,measuring approximately 4 cm in diameter.Grossly,the tumor was located in the skeletal muscle,with a relatively clear boundary.On the cut section,the tumor displayed gray-white and gray-red,translucent and moderate in consistency.Microscopically,the tumor was relatively well-demarcated with focal invasion of skeletal muscles.The tumor was mainly composed of relatively uniform spindle cells arranged in paralleled or intersecting fascicles.The tumor cells showed mild to moderate atypia and some mitoses were seen.Scattered inflammatory cell infiltration and lymphatic follicle formation were identified in some regions,resembling inflammatory myofibroblastic tumor.Immunohistochemically,the tumor cells showed positivity with desmin,MyoD1 and myogenin,diffuse and strong staining with ALK and focal staining with AE1/AE3.FISH displayed the presence of FUS rearrangement and absence of ALK rearrangement,and NGS detected FUS-TFCP2 gene fusion.Conclusion TFCP2-rearranged rhabdomyosarcoma is a novel subtype of RMS with distinctive clinicopathological features,which often occurs in young adults,typically involves the skeleton,particularly the craniofacial bones,and usually shows mixed epithelioid and spindle cell morphology with co-expression of myogenic,epithelial markers and ALK.It is a highly aggressive neoplasm with poor prognosis.