<i>PDGFRA::USP8</i> Fusion in a Cutaneous Inflammatory Myofibroblastic Tumor, Highlighting Genetic Pleiotropy of Kinase Gene Fusions in Soft Tissue Neoplasms

USP8 fusions have recently been described in neoplasms in the provisional category of calcified chondroid mesenchymal neoplasm (CCMN). Here, we describe a cutaneous inflammatory myofibroblastic tumor (IMT) on the upper leg of a 24-year-old male harboring the same fusion product. The tumor showed a morphology typical of IMT, including a concomitant inflammatory infiltrate; in addition, there was strong immunohistochemical PDGFRα overexpression. Methylation profiling (Sarcoma classifier v12.2) was consistent with IMT (calibrated score 0.99). Herein, we review other soft tissue tumors with PDGFRA fusions, emphasizing PDGFRA::USP8 fusions, further highlighting the genetic pleiotropy of kinase gene fusions in soft tissue tumors. In addition, this case expands the landscape of kinase fusions in IMT, presented by an extremely rare cutaneous IMT.