A 19-year-old presents with a 14 cm right ovarian mass and elevated AFP 420 ng/mL, normal beta-hCG. The most likely histological diagnosis is:

• A Immature teratoma
• B Embryonal carcinoma
• C Endodermal sinus tumour (yolk sac tumour) ✓
• D Dysgerminoma

Explanation

Markedly elevated AFP is the hallmark tumour marker of yolk sac tumour (endodermal sinus tumour). Histologically it shows Schiller-Duval bodies (perivascular glomeruloid structures). Dysgerminoma elevates LDH and beta-hCG (syncytiotrophoblastic cells). Immature teratoma elevates AFP mildly. Embryonal carcinoma elevates both AFP and beta-hCG. The dramatic AFP elevation here is most consistent with yolk sac tumour.

Reference: Shaw's Textbook of Gynaecology, 17th ed.

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Written and medically reviewed by the StethoPrep medical team.