Magro Gaetano, Broggi Giuseppe, Zin Angelica, Di Benedetto Vincenzo, Meli Mariaclaudia, Di Cataldo Andrea, Alaggio Rita, Salvatorelli Lucia
Department of Medical and Surgical Sciences and Advanced Technologies, "G. F. Ingrassia", Anatomic Pathology, University of Catania, 95123 Catania, Italy.
Institute of Pediatric Research "Città della Speranza", 35127 Padova, Italy.
Diagnostics (Basel). 2021 Mar 18;11(3):545. doi: 10.3390/diagnostics11030545.
Desmoplastic small round cell tumor (DSRCT) is a rare pediatric soft tissue neoplasm composed of small round tumor cells with prominent stromal desmoplasia, polyphenotypic differentiation and gene fusion. We, herein, present a unique case of DSRCT, exhibiting a pure spindle cell morphology, absence of desmoplastic stroma and showing a novel fusion transcript.
A 12-year-old boy presented multiple intra-abdominal, confluent and mass-forming nodules that affected the entire abdominal and pelvic cavities.
Histologically, the nodules were composed of spindle cells with scant cytoplasm and oval nuclei arranged into short, intersecting fascicles and set in a scant, non-desmoplastic, stroma. Immunohistochemically, neoplastic cells were stained with vimentin, desmin, WT-1 (C-terminus antibodies) and EMA. Reverse-transcriptase polymerase chain reaction (RT-PCR) analysis showed the presence of an unusual chimeric transcript, composed of an in-frame junction of exon 9 of to exon 7 of , confirming the histological diagnosis of DSRCT.
The present case contributes to widen the morphological spectrum of this entity; notably, the additional presence of a novel chimeric fusion transcript contributes to making the present case even more unique. Whether the detection of the above-mentioned fusion transcripts could explain the unusual morphology of the tumor remains to be established.
促结缔组织增生性小圆细胞肿瘤（DSRCT）是一种罕见的儿童软组织肿瘤，由具有显著间质促结缔组织增生、多表型分化和基因融合的小圆肿瘤细胞组成。在此，我们报告一例独特的DSRCT病例，其表现为纯梭形细胞形态，无促结缔组织增生性间质，并显示一种新的融合转录本。
一名12岁男孩出现多个腹腔内融合性肿块结节，累及整个腹腔和盆腔。
组织学上，结节由梭形细胞组成，胞质稀少，椭圆形核排列成短的交叉束状，位于稀少的、无促结缔组织增生的间质中。免疫组织化学检查显示，肿瘤细胞波形蛋白、结蛋白、WT-1（C端抗体）和EMA染色阳性。逆转录聚合酶链反应（RT-PCR）分析显示存在一种不寻常的嵌合转录本，由 外显子9与 外显子7的读码框内连接组成，证实了DSRCT的组织学诊断。
本病例有助于拓宽该实体的形态学谱；值得注意的是，新嵌合融合转录本的额外存在使本病例更加独特。上述融合转录本的检测是否能解释肿瘤的异常形态仍有待确定。
