BCOR–CCNB3‐positive soft tissue sarcoma with round‐cell and spindle‐cell histology: a series of four cases highlighting the pitfall of mimicking poorly differentiated synovial sarcoma

• DOI: 10.1111/his.13001
• Publication Date: 2016-05-26T13:54:49Z
• Authors: Wan‐Shan Li; I‐Chuang Liao; Mei‐Chin Wen; Howard Haw‐Chang Lan; Shih‐Chen Yu; Hsuan‐Ying Huang
• Keywords: CD99; Clear-cell sarcoma; Histology; Spindle cell sarcoma

BCOR-CCNB3 sarcoma is a genetically defined undifferentiated malignancy with Ewing (ES)-like round cells, and preferentially affects the bones of male adolescents. Sarcomas harbouring rarely arise from soft tissues; therefore, we aimed to report four cases expand clinicopathological spectrum.By reverse transcription polymerase chain reaction confirmatory sequencing, detected transcript in primary sarcomas deep musculature patients, comprising two teenagers (aged 14 17 years) adults 34 44 years). The tumours originated back (n = 2), pelvis 1), thigh were 70-140 mm size (mean, 107 mm). All showed sheets primitive or ovoid cells vesicular nuclei, active mitosis (28-41/10 high-power fields), variably prominent nucleoli, geographical necrosis. This major component transformed into fascicles elongated spindle staghorn vessels myxoid reticular stroma, accounting for 10-50% areas. positive CD99, three TLE1, one was EMA, indicating poorly differentiated synovial (PDSSs). Nuclear cyclin B3 reactivity present all cases, but not molecularly confirmed atypical ESs PDSSs. At last follow-up (median, 13.5 months), patient had died lung metastasis, alive tumours, tumour-free.BCOR-CCNB3-positive may primarily occur tissues show PDSS-mimicking round-cell spindle-cell histology aggressive behaviour. Cyclin useful selecting candidates molecular testing.