Stage <scp>IIIC</scp> Bilateral Dysgerminoma in a 16‐Year‐Old Phenotypic Female With 46,XY Complete Gonadal Dysgenesis and Primary Amenorrhea: A Case Report

Dysgerminoma, the most common malignant ovarian germ cell tumor, has a significantly increased incidence in individuals with 46,XY complete gonadal dysgenesis (Swyer syndrome). However, primary amenorrhea is the hallmark presentation of Swyer syndrome in adolescence. This case highlights the critical intersection of these conditions and the oncologic risks of diagnostic delay. A 16-year-old phenotypic female presented with primary amenorrhea. Physical examination revealed normal secondary sexual characteristics and unremarkable pelvic findings. Laboratory evaluation revealed hypergonadotropic hypogonadism with markedly elevated FSH and LH levels. Karyotype analysis revealed a 46,XY chromosomal complement, diagnosing Swyer syndrome. Imaging identified multiple pelvic masses, including a 10.4 cm anterior uterine mass and a para-aortic mass, highly suspicious for malignancy. Exploratory laparotomy with tumor resection and staging confirmed bilateral ovarian dysgerminoma with para-aortic and pelvic lymph node metastasis, classified as FIGO Stage IIIC (pT1bN1Mx). The patient was referred for adjuvant chemotherapy. This case underscores that primary amenorrhea with hypergonadotropic hypogonadism mandates karyotype analysis to exclude 46,XY DSD and its associated high risk of gonadal malignancy. Symptomatic treatment without definitive etiological investigation can lead to dangerous delays, allowing for progression to advanced cancer. A prompt, systematic diagnostic approach is essential to prevent serious oncologic sequelae in these patients.