Recent molecular studies on intimal sarcomas, including PAIS, have demonstrated recurrent amplification of MDM2, MDM4, and CDK6, which appear to be largely mutually exclusive.12) In addition, co-amplification of PDGFRA, CDK4, and TERT has been reported,13) indicating alternative pathways for tumor progression. Here, MDM4 is linked to partial androgen insensitivity syndrome.