Solitary Fibrous Tumor of Kidney : STAT6

Solitary fibrous tumor (SFT) of kidney: Primary solitary fibrous tumor of the kidney has to be differentiated from several mesenchymal neoplasms arising in the kidney, including monophasic synovial sarcoma, angiomyolipoma, leiomyoma, low-grade leiomyosarcoma, and schwannoma. The diagnosis of SFT is supported by positivity for STAT6 (shown here), CD34, BCL2, and CD99 and lack of expression of cytokeratin, smooth muscle actin, desmin, S100 protein, CD31, and CD117. Nuclear expression of STAT6 or demonstration of NAB2-STAT6 gene fusion by FISH is highly sensitive and specific for the diagnosis of SFTs. Further discussion of SFT, including its molecular pathogenesis can be found here.