A Rare Case of Lower Limb Sarcoma With BCOR-CCNB3 Mutation: Diagnosis and Treatment

In the past, BCOR-CCNB3 sarcoma was believed to be comparable to Ewing's sarcoma; however, current research has proven that it is, in reality, a distinct type of the illness, now classified as a distinct entity under undifferentiated round cell sarcomas. This tumour most frequently affects teenagers and young adults, and it is more prevalent in men. It can form in both bone and soft tissue, and it appears most frequently in the pelvis, lower extremities, and paraspinal region. Here, we describe a case of a soft tissue tumour in the proximal posterior portion of the right thigh of a 12-year-old male that was subsequently shown to be a BCOR-CCNB3 fusion using genetic analysis.

Systemic treatments and outcomes in CIC-rearranged Sarcoma: A national multi-centre clinicopathological series and literature review

CIC‐rearranged sarcoma is a recently established, ultra‐rare, molecularly defined sarcoma subtype. We aimed to further characterise clinical features of CIC‐rearranged sarcomas and explore clinical management including systemic treatments and outcomes.

Ewing Sarcoma and Ewing-Like Sarcoma and the Role of NKX2.2 Immunoreactivity

Ewing sarcoma (ES) belongs to the family of "small round blue cell" tumors and its diagnosis currently involves a combination of immunostaining and molecular analysis. However, due to significant histological overlap with other tumors of the same family, accurate diagnosis has historically involved combining these results with clinical correlation. Recently, multiple studies have analyzed the role of NKX2.2 immunopositivity in the diagnosis of ES. NKX2.2, a downstream target of the Ewing sarcoma breakpoint region-Friend leukemia integration 1 (EWSR1-FLI1) fusion, has been identified as a potential stain to differentiate ES and Ewing-like sarcoma from other small round blue cell tumors. In this study, we examine the histopathological interpretation of five patients. Four cases showed fluorescent in situ hybridization (FISH)-identified EWSR1 rearrangement. In one case, rearrangements of EWSR1 or FUS could not be detected, and a diagnosis of Ewing-like sarcoma was rendered. NKX2.2 was immunopositive in all five cases. Based on this limited dataset, NKX2.2 immunopositivity can significantly support the diagnosis of ES and has the potential to support the diagnosis of fusion-undetected Ewing-like sarcoma in appropriate clinical and histologic settings.