Upregulation of NKX2.2, a target of EWSR1/FLI1 fusion transcript, in primary renal Ewing sarcoma

• Main Authors: Yoshinari Yamamoto, Kazuto Yamazaki, Yasuo Ishida
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2015-01-01
• Series: Journal of Cytology
• Subjects: CD99; Ewing sarcoma; immunocytochemistry; kidney neoplasm; NKX2.2
• Online Access: http://www.jcytol.org/article.asp?issn=0970-9371;year=2015;volume=32;issue=1;spage=30;epage=32;aulast=Yamamoto

Renal Ewing sarcoma (ES) is a rare malignant tumor characterized by fusion of the EWSR1 gene with a member of the ETS family of oncogenes, arising at a specific chromosomal translocation. Diagnosis of ES can be problematic, especially from cytological or small bioptical specimens because the differential diagnoses comprising a diverse group of small round blue cell tumors (SRBCTs). We report a case of primary renal ES in a young male, which had a t(11;22) (q24;q12) chromosome translocation encoding a type2 EWSR1/FLI1 fusion transcript. The tumor cells showed diffuse cytoplasmic immunoreactivity for CD99 and diffuse nuclear immunoreactivity for NKX2.2, an important oncogenic transcriptional target of EWSR1/FLI1, not only in the histological, but also in the cytological specimens. From the results of this case, we speculate that NKX2.2, in combination with CD99, may be a useful immunocytochemical marker to distinguish renal ES from other SRBCTs of kidney.