CIC-rearranged sarcomas (CRS) are a group of heterogeneous tumors which mostly occur in the soft tissues of limbs and trunk, and are highly invasive with poor prognosis. Here, we describe a rare case of CRS that occurred in the left kidney with a CIC-LEUTX rearrangement.
A 45-year-old male was admitted to hospital with a dry cough for more than two months without obvious cause. Physical examination and laboratory tests revealed no notable abnormality. The CT scan demonstrated a mass in the left kidney and multiple nodules in both lungs. The percutaneous core needle biopsy showed similar histomorphology and immunophenotype of small round cell malignant tumors. Genetic test revealed a CIC-LEUTX gene fusion.
We present a rare primary renal CRS with multiple pulmonary metastases, and LEUTX is confirmed as the fusion partner of CIC gene for the first time in a renal case.

CIC-rearranged sarcoma is a rare and extremely aggressive tumor that occurs mainly in soft tissues. Despite the fact that identification of a characteristic genetic rearrangement is necessary to verify the diagnosis, in most cases, the correct diagnosis can be made by comparing histological signs and a characteristic immunophenotype, which greatly speeds up the diagnosis. The article describes a case of CIC-rearranged sarcoma in a 14-year girl with the successful application of the CWS-2009 treatment protocol.
CIC-перестроенная саркома является редкой и крайне агрессивной опухолью, которая возникает преимущественно в мягких тканях. Несмотря на то что для верификации диагноза необходима идентификация характерной генетической перестройки, в большинстве случаев верный диагноз может быть поставлен при сопоставлении гистологических признаков и характерного иммунофенотипа, что значительно ускоряет диагностику. В статье описано наблюдение CIC-перестроенной саркомы у 14-летней девочки с успешным применением протокола лечения CWS-2009.

CIC-rearranged sarcomas are rare mesenchymal neoplasms belonging to the family of undifferentiated small round cell sarcomas. This report details the case of a 45-year-old man presenting with symptoms of mediastinal compression, radiological diagnosis of a mediastinal mass and rapid evolution to full-blown superior vena cava syndrome. The emergency was successfully managed with a pharmacological approach. Formulation of a pathological diagnosis of CIC-rearranged sarcoma was initially supported by fluorescence in situ hybridisation findings and later validated by next-generation sequencing, which showed CIC-DUX4 gene fusion. A chemotherapy regimen was started with immediate benefits for the patient. The spectrum of pathological entities able to cause superior vena cava syndrome is wide, and recognition of rare causes is important to tailor the therapeutic approach to the specific disease. This is, to the best of our knowledge, the first report of CIC-rearranged sarcoma presenting with superior vena cava syndrome.

A 16-year-old male was admitted to the hospital for weakness of both lower extremities. Magnetic resonance imaging revealed an intraspinal extramedullary subdural mass at the thoracic 9 level. Microscopically, the tumor cells were small to medium sized and round to ovoid in shape. They were distributed in diffuse sheets or showed nodular appearance. The nucleus of the tumor had mild-to-moderate atypia, with vesicular chromatin and prominent nucleoli. A smaller proportion of tumor cells demonstrated rhabdoid morphology. Focal myxoid stromal change was present, in which tumor cells exhibited spindle shapes. Approximately two mitoses were counted per 10 high-power fields. No necrosis was observed. The tumor cells were focal positive for CD99; multifocal positive for WT1; diffuse positive for nestin, synaptophysin, and D2-40; partial positive for GFAP; focal positive for desmin and SSTR2; and scattered positive for S-100 protein. The Ki-67 labeling index was approximately 20%. Genetic testing revealed CIC-LEUTX gene fusion. Considering the patient\'s history, clinical data, pathological findings and genetic findings, we rendered a rare tumor named CIC-rearranged sarcoma with CIC-LEUTX gene fusion.

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原发于婴儿心脏的恶性肿瘤极为罕见，该文报道1例发生于婴儿心脏的CIC重排肉瘤。患儿女，11个月，因纳差12 d，气短3 d、加重1 d入院。影像学检查示右心室占位、心包积液；手术大部分切除肿瘤。镜下肿瘤细胞呈巢片状分布，由圆形、卵圆形细胞及少量胖梭形细胞构成，胞质透亮或嗜酸性，核形不规则，部分核仁突出，核分裂象易见，伴地图状坏死；免疫组织化学CD99斑块状阳性，Fli1、WT1弥漫阳性；荧光原位杂交检测示CIC断裂重排，EWSR1未见重排。.

BACKGROUND Undifferentiated small blue round cell sarcomas with CIC-DUX4 translocation differ morphologically and in clinical outcomes from other types of sarcoma. Although classified by the World Health Organization as undifferentiated sarcomas, it is unclear whether these tumors are variants of Ewing\'s sarcoma or a distinct entity. This report describes a round cell sarcoma with CIC-DUX4 translocation that presented clinically as a phlegmon. CASE REPORT A 31-year-old African American man presented with a mass in the right upper abdominal quadrant. Examination at a local hospital suggested an intra-abdominal abscess, and incision and drainage were performed. One week later, he returned with increased pain and bloody drainage from the incision site. Computed tomography showed a complex solid-cystic area measuring 7.8 cm suggesting a large phlegmon/abscess or neoplasm. Histologically, the sarcomatous malignancy was cellular, multinodular, and necrotic, with cells having round-ovoid to spindled nuclei and variable amounts of pale cytoplasm. Immunohistochemically, the mass was focally positive for CD99, but much less positive than an Ewing sarcoma. The mass also showed diffuse nuclear positivity for WT-1 and ETV4, but was negative for desmin. Fluorescence in-situ hybridization showed positivity for CIC-DUX4 gene fusion, resulting in a final diagnosis of round cell sarcoma with CIC-DUX4 translocation. The patient has completed 14 cycles of chemotherapy with no evidence of metastasis or local recurrence. CONCLUSIONS A round cell sarcoma with CIC-DUX4 translocation can present clinically as a phlegmon with pleomorphic morphology. Early tumor identification by molecular analysis and early initiation of treatment can improve patient prognosis.

CIC-rearranged sarcomas (CRSs) have recently been characterized as a distinct sarcoma subgroup with a less favorable prognosis compared to other small round cell sarcomas. CRSs share morphologic features with Ewing\'s sarcoma and prior to 2013 were grouped under undifferentiated sarcomas with round cell phenotype by the WHO classification. In this report, whole-genome sequencing and RNA sequencing were performed for an adolescent male patient with CRS who was diagnosed with undifferentiated pleomorphic sarcoma (UPS) by three contemporary institutions. Somatic mutation analysis identified mutations in IQGAP1, CCNC, and ATXN1L in pre- and post-treatment tissue samples, as well as a CIC-DUX4 fusion that was confirmed by qPCR and DUX4 immunohistochemistry. Of particular interest was the overexpression of the translation factor eEF1A1, which has oncogenic properties and has recently been identified as a target of the investigational agent plitidepsin. This case may provide a valuable waypoint in the understanding and classification of CRSs and may provide a rationale for targeting eEF1A1 in similar soft tissue sarcoma cases.

Capicua transcriptional repressor (CIC)-rearranged sarcomas are part of the group of Ewing-like sarcomas or atypical Ewing sarcomas which, thanks to the progress in molecular diagnosis, are being defined by particular genetic abnormalities separating this group into distinct entities with their own particular histological and immunohistochemical features, as well as different survival outcomes. We report the case of a healthy 28-year-old female presenting with a tender lesion on her forearm which after ultrasound examination was clinically favored to represent an infected sebaceous cyst. Hematoxylin-eosin staining showed a lobulated neoplasm within the subcutis composed of poorly differentiated epithelioid to round cells with a small amount of amphophilic cytoplasm. Frequent mitotic figures and tumor necrosis were present. Immunohistochemical studies showed patchy focal CD99 membranous positivity, negative WT1 and TLE1 staining and diffuse nuclear positivity for ETV4 (performed at outside laboratory). FISH analysis showed significant CIC rearrangement enabling a final diagnosis of an undifferentiated small round cell sarcoma harboring the t(4;19)(q35;q13.1) and CIC-DUX4 fusion. This case shows the importance of awareness of this entity as, unlike Ewing sarcoma, these lesions present in the soft tissues rather than bone and may, as in this case, arise in the superficial soft tissues and be submitted to a dermatopathology practice.

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