An unusual case is presented of advanced dysgerminoma in a patient with Swyer syndrome, 46,XY pure gonadal dysgenesis. Unexpected regional invasion necessitated bowel resection, total abdominal hysterectomy, and bilateral salpingogonadectomy for a complete en bloc excision of the primary tumor mass and the dysgenetic gonads. This report illustrates the possible need for extensive operative resection in patients with Swyer syndrome.