A 32-year-old woman presents with palpitations, weight loss, heat intolerance, and tremor. Thyroid examination is normal and thyroid autoantibodies are negative. Ultrasound shows a 6 cm right adnexal mass. TSH is suppressed with normal serum hCG. What is the most likely cause?
- A Struma ovarii ✓
- B Toxic multinodular goitre
- C Granulosa cell tumour
- D Serous borderline tumour
Correct answer: A. Struma ovarii
Explanation
Struma ovarii is a monodermal variant of mature cystic teratoma composed predominantly of thyroid tissue and is a recognised cause of thyrotoxicosis with a normal neck gland. A structurally and functionally normal thyroid excludes toxic goitre and Graves disease as sources. Granulosa cell tumours secrete oestrogen rather than thyroxine, and epithelial borderline tumours have no hormonal secretion.
Reference: Williams Gynecology, 4th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.