46,XX pure gonadal dysgenesis presenting with a massive yolk sac tumor: a diagnostic and surgical challenge - a rare case report.

Introduction and importance: Pure gonadal dysgenesis (PGD) is a rare condition that presents as phenotypic female individuals with nonfunctional gonads. The development of malignant germ cell tumors like yolk sac tumors (YSTs) in PGD is exceedingly rare, with a less than 5% risk in 46XX PGD and a 30-40% risk in 46XY PGD. We present a case of YST in a 27-year female with PGD. Case presentation: A 27-year-old woman with primary amenorrhea presented with acute lower abdominal pain and a 20 cm adnexal mass. Hormonal assays showed hypergonadotropic hypogonadism. Alpha-fetoprotein (AFP) exceeded 2000 ng/mL. Magnetic resonance imaging (MRI) demonstrated a large abdominopelvic mass and infantile uterus. Karyotype confirmed 46,XX. The patient underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy followed by bleomycin, etoposide, and cisplatin (BEP) chemotherapy. Post-treatment AFP levels normalized, and six-month imaging showed no residual disease. Clinical discussion: The genetic basis of PGD is complex, involving numerous genes that result in nonfunctional streak gonads. YSTs are aggressive malignancies typically found in dysgenetic gonads, which are prone to neoplastic transformation, though they are rare presentation. Imaging such as ultrasonography and MRI plays a key role in diagnosing both the extent of gonadal dysgenesis and any associated tumors. Surgical pathway is the cornerstone of treatment with BEP regimen as adjuvant chemotherapy. Conclusion: This rare case highlights the importance of considering YST in PGD patients with abdominal masses and elevated tumor markers and demonstrates that prompt surgical and chemotherapeutic intervention yields favorable outcomes.