A 14-year-old girl with primary amenorrhoea is evaluated for delayed puberty. Karyotype shows 45,X/46,XY mosaicism. Ultrasound reveals bilateral streak gonads. If a gonadectomy specimen shows a tumour composed of nests of germ cells and sex cord derivatives with rounded eosinophilic deposits resembling Call-Exner bodies, what is the tumour and why must the gonads be removed?

• A Yolk sac tumour, risk of relapse despite normal AFP
• B Juvenile granulosa cell tumour, risk of recurrence if conservative surgery done
• C Dysgerminoma, risk of haematogenous metastasis
• D Gonadoblastoma, high risk of progression to invasive dysgerminoma ✓

Explanation

Gonadoblastoma is a benign mixed tumour of germ cells and sex cord elements occurring almost exclusively in dysgenetic gonads carrying Y-chromosome material. Although itself benign, it acts as a precursor lesion, and invasive dysgerminoma develops in up to 50 percent if the gonad is retained, which is the rationale for prophylactic gonadectomy. Pure dysgerminoma and yolk sac tumour lack the biphasic nested pattern.

Reference: Berek and Novak's Gynecology, 16th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.