Swyer syndrome complicated by rapidly progressive invasive ovarian dysgerminoma with bladder and rectal direct invasion: a rare case report.

A 16-year-old patient with a female social gender was admitted because of "a pelvic mass detected for one year", accompanied by primary amenorrhea and poorly developed secondary sexual characteristics. Laboratory tests after admission showed elevated levels of follicle-stimulating hormone and luteinizing hormone, decreased estradiol level, and increased levels of β-human chorionic gonadotropin and carbohydrate antigen 125. Imaging examinations suggested multiple masses in the bilateral adnexal regions and abdominopelvic cavity. Karyotype analysis showed 46, XY. Exploratory laparotomy was performed. A huge right adnexal mass and multiple pelvic lesions were observed intraoperatively. Intraoperative frozen-section pathological examination suggested a malignant germ cell tumor, favoring dysgerminoma. Therefore, cytoreductive surgery was performed. Postoperative histopathological and immunohistochemical findings supported the diagnosis of dysgerminoma, and malignant tumor cells were detected in peritoneal lavage fluid. The final diagnosis was Swyer syndrome complicated by ovarian dysgerminoma, stage IIB. After surgery, the patient received four cycles of bleomycin, etoposide and cisplatin chemotherapy. During follow-up until April 2025, the carbohydrate antigen 125 level decreased to the normal range, and no definite recurrence was observed on imaging. This case suggests that karyotype analysis and gonadal assessment should be performed as early as possible in patients with primary amenorrhea, gonadal dysgenesis or abnormal pubertal development. Patients with Y-chromosome material are at risk of gonadal tumors. After diagnosis, multidisciplinary management involving reproductive endocrinology, gynecologic oncology, genetic counseling and psychological support is required.