Among the STSs included in the study, those with strong expression in more than 50% of the neoplastic cells, 22 cases were submitted for the assessment of mutations in exons 8, 9, and 11 of the c-kit gene: six sarcomas of fibroblastic origin (two fibrosarcomas and four myxosarcomas), six PWTs, three liposarcomas, five RMSs, and two MNSTs. The gene discussed is KIT; the disease is Bannayan-Riley-Ruvalcaba syndrome.