Abdominal Mass in a Phenotypic Female with 46,XY Differences in Sex Development

We present a case of a large intra-abdominal mass found to be localized pure seminoma within a retained gonad of a 53-year-old phenotypic female with 46,XY differences in sex development (DSD) and androgen insensitivity syndrome (AIS). Our management included extirpation of the mass with contralateral gonadectomy. Historically, patients with AIS would undergo gonadectomy to mitigate the lifetime risk of testicular germ cell tumor development; however, growing evidence suggests safety in retention and surveillance of these gonads into adulthood. This case highlights the importance of lifetime surveillance of patients with 46,XY DSD who elect to retain their gonads.