RESUMO
Sarcomas with BCOR genetic alternations, formerly treated as Ewing-like sarcomas, are malignant tumors with a poor prognosis. They have been classified under the category of undifferentiated small round cell sarcomas of bone and soft tissue since 2020. There are only a few reports on surgical treatment for these sarcomas, as they are extremely rare, and no specific treatment has been established. Among them, there have been no reports on the treatment of patients with intracardiac invasion. We report herein the case of intracardiac invasion of a rare sarcomas with BCOR genetic alternations. The patient is a 14-year-old girl who presented to the hospital with a chief complaint of left upper arm pain. Computed tomography (CT) showed tumors in the left axilla and left thoracic cavity, and after biopsies of each, we diagnosed the patient with sarcomas with BCOR genetic alternations. Although chemotherapy was planned, echocardiography revealed a mobile tumor in the left atrium, we decided to perform surgical procedure before chemotherapy to reduce the risk of embolism and sudden death. The tumor invaded directly the left upper pulmonary vein and extended into the left atrium. Since right lung metastasis was suspected, we considered the en bloc tumor resection while preserving the left lung. However it was difficult because the tumor invaded into the vicinity of the lower lobe bronchus. Concerned about extracardiac seeding, we resected the tumor as much as possible intravascularly. Although there was residual tumor, chemotherapy was started immediately after surgery, and the tumor has shrunk in size. We are planning to remove the entire tumor after several courses of chemotherapy.
RESUMO
Ewing's sarcoma and Ewing-like sarcoma are highly invasive sarcomas predominantly characterized by the presence of small round cells. Although certain morphological and immunophenotypical characteristics are similar between the two sarcomas, there are obvious differences in the disease sites, clinical manifestations, prognoses, and treatment responses. Additionally, Ewing-like sarcomas lack the typical molecular characteristics of Ewing's sarcoma. A growing body of evidence shows that Ewing-like sarcomas constitute a different disease type with unique characteristics, and are not just a subtype of Ewing's sarcoma. The discovery of novel molecular genetic tests has significantly aided the reevaluation of the classification of small round cell tumors. This article aims to review the recent progress in the research on Ewing's sarcoma and the major subclasses of Ewing-like sarcoma characterized thus far: CIC rearrangement sarcoma, BCOR rearrangement sarcoma, non-ETS family gene rearrangement sarcoma, and undifferentiated small round cell sarcoma.
RESUMO
Background & objectives: Certain genetically defined undifferentiated round cell sarcomas, namely BCOR-CCNB3 and CIC-DUX4 positive, have been described. Here we present detailed clinicopathologic features and molecular results in such cases. Methods: Fifty one cases of undifferentiated round cell sarcomas, including 32 cases, tested for BCOR-CCNB3 and CIC-DUX4 fusions, by reverse transcription polymerase chain reaction technique and 44 tumours, for CCNB3 immunostaining, were analyzed. Results: Twenty seven (52.9%) tumours occurred in males and 24 (47%) in females; in soft tissues (38; 74.5%), commonly, trunk and extremities and bones (13; 25.4%), frequently, femur and tibia. Five of 32 (15.6%) tested cases were positive for BCOR-CCNB3 fusion and seven (21.8%) for CIC-DUX4 fusions. Histopathologically, CIC-DUX4-positive sarcomas comprised nodular aggregates of round to polygonal cells, containing hyperchromatic nuclei, prominent nucleoli and moderate cytoplasm, with focal myxoid stroma and variable necrosis, in certain cases. BCOR-CCNB3- positive sarcomas mostly comprised diffusely arranged, round to oval to short spindly cells with angulated nuclei, vesicular chromatin, inconspicuous nucleoli and interspersed vessels. Immunohistochemically, tumour cells were positive for MIC2 in 24 of 49 (48.9%) and CCNB3 in 12 of 44 (27.2%) cases. Four of five BCOR-CCNB3-positive sarcomas showed CCNB3 immunostaining and 6 of 7 CIC-DUX4-positive sarcomas displayed WT1 immunostaining. Most patients (27/37) (72.9%) underwent surgical resection and chemotherapy. Median overall survival was 12 months, and disease-free survival was seven months. Interpretation & conclusions: Undifferentiated round cell sarcomas are rare; mostly occur in soft tissues of extremities, with CIC-DUX4 positive, as these are relatively more frequent than BCOR-CCNB3 positive sarcomas. CCNB3 and WT1 are useful immunostains for triaging such cases for BCOR-CCNB3 and CIC-DUX4 fusion testing, respectively. Overall, these are relatively aggressive tumours, especially CIC-DUX4-positive sarcomas.