A 28-year-old woman undergoes unilateral salpingo-oophorectomy for a 12 cm ovarian tumor. Histology shows a teratoma containing thyroid tissue that is the predominant component and shows all microscopic features of a well-differentiated follicular carcinoma. This is BEST classified as:
- A Immature teratoma grade 2 with thyroid differentiation
- B Carcinoid tumor of teratomatous origin
- C Struma ovarii with malignant transformation (malignant struma ovarii) ✓
- D Dysgerminoma with glandular elements
Explanation
Struma ovarii is a specialized monodermal teratoma composed predominantly (>50%) of thyroid tissue. When this tissue exhibits features of thyroid carcinoma, it is termed malignant struma ovarii (the most common malignant variant being follicular carcinoma). It accounts for <5% of struma ovarii cases. Management parallels thyroid cancer management — total thyroidectomy and radioiodine ablation are considered after fertility-sparing surgery. Immature teratoma grading is based on the amount of immature neural tissue, not thyroid elements, and dysgerminoma is a germ cell tumor without glandular structure.
Reference: Shaw's Textbook of Gynaecology, 17th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.