A 23-year-old woman is evaluated for a rapidly growing pelvic mass. Serum calcium is 13.8 mg/dL (corrected) and PTH is suppressed; phosphorus is low. She has no bone disease, malignancy elsewhere, or vitamin D excess. CT shows a large unilateral solid ovarian mass. Which tumour explains both findings?

• A Adult granulosa cell tumour
• B Juvenile granulosa cell tumour
• C Yolk sac tumour
• D Small cell carcinoma of the ovary, hypercalcaemic type ✓

Explanation

Small cell carcinoma of the ovary, hypercalcaemic type, affects girls and young women, produces PTH-related protein causing humoral hypercalcaemia of malignancy, and presents as a large unilateral aggressive mass. Suppressed PTH with high corrected calcium in a young woman with an ovarian mass is the discriminating picture. Yolk sac tumour raises AFP, granulosa cell tumours raise inhibin and cause oestrogen effects, and neither is linked to hypercalcaemia. This tumour carries a poor prognosis despite platinum-based therapy.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.