Desmoplastic small round cell tumor with atypical immunohistochemical profile and rhabdoid-like differentiation  

作　　者：Li Liang Nina Tatevian Meenakshi Bhattacharjee Kuojen Tsao John Hicks 

机构地区：[1]Department of Pathology and Laboratory Medicine,the University of Texas Health Science Center at Houston,Houston,TX 77030,United States [2]Department of Pediatric Surgery,the University of Texas Health Science Center at Houston,Houston,TX 77030,United States [3]Department of Pathology,Texas Children’s Hospital,Houston,TX 77030,United States

出　　处：《World Journal of Clinical Cases》2014年第8期367-372,共6页世界临床病例杂志

基　　金：Supported by Department of Pathology,the University of Texas Health Science Center at Houston,United States

摘　　要：Desmoplastic small round cell tumor(DSRCT) is a rare,aggressive malignant neoplasm of unknown origin, and is comprised of small round cells with a characteristic desmoplastic stroma. DSRCT typically expresses epithelial, mesenchymal and neural markers simultaneously. We describe a case of DSRCT with an atypical immunohistochemical profile and rhabdoid-like tumor cells on electron microscopy. In the present case, the neoplastic cells were positive only for vimentin, desmin(cytoplasmic membranous pattern) and CD56,and negative for smooth muscle actin, synaptophysin,CD117, CD45, myogenin, CAM5.2, pancytokeratin,WT1, EMA, CD99, neurofilament, CD34 and p53. Ki67 showed a low proliferative activity. Electron microscopy showed focal rhabdoid differentiation. However, INI-1(SNF-5/BAF47) demonstrated preservation of nuclear positivity in the neoplastic cells. Cytogenetic studies showed translocation t(11;22)(p13;q12) confirming an EWSR1-WT1 translocation characteristic for DSRCT, and t(1;15)(q11;p11.2) of unknown significance. This case is a diagnostic challenge because of atypical immunohistochemical profile and cytogenetic study is crucial in rendering the correct diagnosis.Desmoplastic small round cell tumor(DSRCT) is a rare,aggressive malignant neoplasm of unknown origin, and is comprised of small round cells with a characteristic desmoplastic stroma. DSRCT typically expresses epithelial, mesenchymal and neural markers simultaneously. We describe a case of DSRCT with an atypical immunohistochemical profile and rhabdoid-like tumor cells on electron microscopy. In the present case, the neoplastic cells were positive only for vimentin, desmin(cytoplasmic membranous pattern) and CD56,and negative for smooth muscle actin, synaptophysin,CD117, CD45, myogenin, CAM5.2, pancytokeratin,WT1, EMA, CD99, neurofilament, CD34 and p53. Ki67 showed a low proliferative activity. Electron microscopy showed focal rhabdoid differentiation. However, INI-1(SNF-5/BAF47) demonstrated preservation of nuclear positivity in the neoplastic cells. Cytogenetic studies showed translocation t(11;22)(p13;q12) confirming an EWSR1-WT1 translocation characteristic for DSRCT, and t(1;15)(q11;p11.2) of unknown significance. This case is a diagnostic challenge because of atypical immunohistochemical profile and cytogenetic study is crucial in rendering the correct diagnosis.

关 键 词：DESMOPLASTIC small round cell tumor ULTRASTRUCTURE CYTOGENETICS RHABDOID cells EWSR1-WT1 

分 类 号：R738.6[医药卫生—肿瘤]