Primary desmoplastic small round cell tumor of the kidney: a case report in a 14-year-old girl with molecular confirmation.

We report a case of desmoplastic small round cell tumor (DSRCT) arising in the kidney of a 14-year-old female. The subject presented with gross hematuria. Medical imaging uncovered a left renal mass without regional or metastatic extension. The tumor showed morphological, immunohistochemical, and molecular features of DSRCT. Immunostaining revealed polyphenotypic differentiation. Molecular analysis detected the fusion transcript resulting from the t(11;22)(p13;q12) reciprocal translocation, which characterized this neoplasm. Desmoplastic small round cell tumor is a rare, aggressive neoplasm that mainly affects young males and that usually presents with widespread abdominal serosal involvement. This unusual localization should lead one to consider this tumor in the differential diagnosis of small blue round cell tumors of the kidney.