Abstract

A female new-born presented with a sacrococcygeal mass with spinal cord compression. A preliminary histologic diagnosis determined a small round blue cell tumor and immunohistochemical results discarded neuroblastoma, rhabdomyosarcoma, rhabdoid tumor, Ewing or peripheral neuroectodermal tumor (PNET). The results obtained by SNPa showed a chromosome Xp11.4 deletion of 0.9 Mb, where the BCOR gene is located. RT-PCR did not detect the ETV6-NTRK3 or EWSR1-FLI1 fusion, but did reveal the presence of the BCOR-CCNB3 fusion transcript, recently reported in some undifferentiated sarcomas, establishing the diagnosis of “Ewing-like” sarcoma. Analysis of CCNB3 expression by immunohistochemistry showed nuclear overexpression in 100% of tumor cells. The patient received aggressive chemotherapy which reduced the size of the tumor, but ultimately the patient died of liver failure secondary to infection with adenovirus 5 months after diagnosis. While the literature reports the predominance of these tumors in male children or young adults, we present the first case in a female new-born. This finding supports the need for further studies to look for the presence of the BCOR-CCNB3 fusion transcript in younger patients, to achieve an effective sub-classification within undifferentiated sarcomas.

Keywords: BCOR-CCNB3 sarcoma; Undifferentiated sarcoma; “Ewing-like” sarcoma; Small round cell tumor