Bean GR, et al. - Given that DICER1 mutations have been reported mainly in a small subset of adenosarcomas with rhabdomyosarcomatous elements, researchers ascertained if these are specific to the rhabdomyosarcomatous phenotype. For this investigation, they analyzed the clinical, pathologic, and genomic features of 19 müllerian adenosarcomas enriched for tumors with rhabdomyosarcomatous differentiation, as well as eight uterine carcinosarcomas with a rhabdomyosarcoma component. It was noted that carcinosarcomas with rhabdomyosarcomatous differentiation lacked DICER1 mutations, but they exhibited frequent mutations in TP53 (7/8, 88%) and the PI3K/PTEN pathway (6/8, 75%). The outcomes emphasized the importance of DICER1 mutations in müllerian adenosarcoma tumorigenesis and demonstrated that these alterations were not exclusive to heterologous rhabdomyosarcomatous differentiation.