Title : A large ovarian yolk sac tumour masquerading as polycystic ovarian syndrome: A three-year diagnostic delay
Abstract:
A 33-year-old woman (G3P2+1) presented with a three-year history of progressive hirsutism, significant weight gain, and secondary amenorrhoea, initially attributed to polycystic ovarian syndrome (PCOS) in the context of a raised serum testosterone (6.3 nmol/L) and concurrent hypothyroidism (TSH 9.3 mU/L). During endocrinology review, pelvic ultrasound revealed a large complex solid-cystic pelvic mass measuring 21.2 × 13.8 × 23.4 cm, extending from the pelvis to above the umbilicus, with neither ovary separately identifiable. Tumour markers demonstrated a markedly elevated Alpha-Fetoprotein (AFP) of 8,147 KU/L and CA-125 of 78 KU/L. CT thorax, abdomen and pelvis confirmed a 23 cm predominantly cystic mass with solid enhancing components and no evidence of peritoneal or metastatic disease. On clinical examination, the mass was palpable to a size equivalent to a 35–40 week uterus.
Following discussion at the Regional Gynaecology MDT and the specialist Germ Cell Tumour (GCT) MDT at Clatterbridge Cancer Centre, the findings were consistent with an ovarian yolk sac tumour. The GCT MDT recommended surgical resection, nodal sampling, and fluid cytology. The patient underwent elective laparotomy and left salpingo-oophorectomy at a regional cancer centre. Histology and staging were pending at the time of reporting.
This case illustrates a critical diagnostic pitfall: the attribution of hyperandrogenaemia to PCOS without pelvic imaging in a young woman. A serum testosterone exceeding 5 nmol/L in a premenopausal woman warrants urgent pelvic ultrasound to exclude an androgen-secreting or neoplastic ovarian lesion. Furthermore, a markedly elevated AFP (>1,000 KU/L) in a non-pregnant woman of reproductive age is essentially pathognomic of a yolk sac tumour and constitutes a clinical urgency requiring same-day gynaecological oncology referral. The simultaneous presence of hypothyroidism and a progestogenic contraceptive implant provided alternative explanations for all presenting symptoms — amenorrhoea, weight gain, and fatigue — masking the underlying malignancy for approximately three years. This case reinforces the essential role of multi-specialty MDT collaboration in rare gynaecological tumours, ensuring oncologically appropriate surgical planning consistent with national guidance.
Keywords: Ovarian Germ Cell Tumour, Yolk Sac Tumour, Hyperandrogenaemia, Alpha-Fetoprotein, PCOS, Diagnostic Delay, Gynaecological Oncology
