Cytomorphological features and literature review of CIC‐DUX4‐positive sarcoma, confirmed by reverse transcription polymerase chain reaction in a paediatric patient

Abstract

Certain undifferentiated round cell sarcomas characterised by specific underlying genetic fusions have been reported. This case describes cytomorphological and corresponding histopathological, including immunohistochemical features of a rare case of CIC‐DUX4 positive sarcoma, including a literature review of similar reported cases.

Pitfalls in soft tissue cytopathology

“…CIC-rearranged sarcomas should be suspected after the relatively more common rhabdomyosarcoma has been excluded by negative IHC for markers of skeletal muscle differentiation and positive WT1 IHC. The tumour can be confirmed by fluorescence in situ hybridisation (FISH) testing for CIC-rearrangement or by detecting a specific fusion, such as CIC::DUX4, using the reverse transcription polymerase chain reaction (RT-PCR) technique 60,61. The other newly recognised, rare, undifferentiated sarcoma, which more frequently occurs at bone sites in paediatric patients and rarely in the soft tissues, is a BCOR-rearranged sarcoma, including the BCOR::CCNB3-fusion positive sarcoma.…”