Primary retroperitoneal perirenal CIC rearrangement sarcoma: A case report

Primary retroperitoneal perirenal CIC rearrangement sarcoma is rare. The current case report presents a 69-year-old male patient with this pathology, including the clinical features, pathomorphology and immunohistochemistry, and CIC gene rupture detected by fluorescence in situ hybridization (FISH). Furthermore, the relevant literature was reviewed. Histologically, the tumor was composed of diffuse nests of small- to medium-sized juvenile round blue cells with hyperchromatic nuclei, prominent nucleoli and occasional mitotic signs. The tumor involved adipose tissue with no obvious hemorrhagic necrotic foci. Immunohistochemistry indicated scattered expression of CD99 in tumor cells. FISH examination suggested that the CIC gene was fragmented and translocated.