A 22-year-old woman presents with a rapidly enlarging pelvic mass, vomiting and serum calcium corrected to 13.8 mg/dL with normal PTH. There is no bone metastasis on imaging. Laparotomy reveals a unilateral ovarian tumour made of small round blue cells growing in sheets and follicle-like spaces. Which diagnosis fits best?
- A Metastatic breast carcinoma
- B Dysgerminoma with humoral hypercalcaemia
- C Small cell carcinoma of the ovary, hypercalcaemic type ✓
- D Thecoma secreting vitamin D analogue
Correct answer: C. Small cell carcinoma of the ovary, hypercalcaemic type
Explanation
Small cell carcinoma of the ovary, hypercalcaemic type, occurs in young women, produces PTH-related protein driving humoral hypercalcaemia without bone metastases, and shows sheets of small undifferentiated cells with follicle-like spaces. Dysgerminoma rarely causes hypercalcaemia and shows germ cells with lymphocytes, and thecomas secrete oestrogen rather than causing hypercalcaemia.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.