Challenging differential diagnosis of a wild-type gastrointestinal stromal tumour (GIST) or rare reticular perineurioma of the stomach? The role for mutational analysis.

The differential diagnosis of submucosal stomach lesions includes gastrointestinal stromal tumour (GIST), leiomyoma, synovial sarcomas, perineurioma, myxoid chondrosarcoma, myoepithelial tumour and other rare mesenchymal tumours. GISTs are well-defined lesions with distinctive morphologic and histogenetic characteristics that show 95% positive staining for CD117. Differential diagnosis of wild-type GISTs can be challenging.