FISH analysis showed significant CIC rearrangement enabling a final diagnosis of an undifferentiated small round cell sarcoma harboring the t(4;19)(q35;q13.1) and CIC-DUX4 fusion.
Here, using analyses of published whole-genome gene expression microarray data, we identify PAX7 as a gene with significantly increased expression in Ewing sarcoma in comparison to CIC-DUX4round cell sarcoma.
CIC-DUX4round cell sarcoma differs from Ewing sarcoma in that it has more atypical cytologic features and lacks the diffuse membranous CD99 staining pattern characteristic of Ewing sarcoma.
We evaluated BRG1 and INI1 expression in 12 SCCOHTs and in a series of 122 tumors that could mimic SCCOHT morphologically: 9 juvenile granulosa cell tumors, 47 adult granulosa cell tumors, 33 high-grade ovarian serous carcinomas, 9 desmoplastic round cell tumors, 13 Ewing sarcomas (5 from the pelvis and 8 from soft tissues), 1 round cell sarcoma associated with CIC-DUX4 translocation from soft tissue (thigh), 1 case of high-grade endometrial stromal sarcoma of the ovary, and 9 melanomas.
Undifferentiated small round cell sarcoma with t(4;19)(q35;q13.1) CIC-DUX4 fusion: a novel highly aggressive soft tissue tumor with distinctive histopathology.