Fibromyxoid aSoft Tissue Tumor With PLAG1 Fusion-The First Case in an Adult Patient

With the expanding possibilities of human genome research in recent years, the number of cases of soft tissue tumors that we are able to classify into the correct subgroups and to reveal their molecular profile is increasing. Among such tumors, we can also consider neoplasms that have a specific fusion of genes, in our case namely the pleomorphic adenoma gene 1 (PLAG1) and its partner. PLAG1 gene fusions were previously associated mainly with salivary gland pleomorphic adenomas, lipoblastomas, myoepithelial tumors, uterine epitheloid, myxoid leiomyosarcomas, and, recently, with PLAG1-rearranged fibromyxoid soft tissue tumors. To our knowledge, we report the first case of a soft tissue tumor with a PLAG1 fusion gene in an adult. In our case, we detected a new H3-3B::PLAG1 fusion in a soft tissue tumor, which originally appeared as nodular fasciitis.