A 26-year-old woman with palpitations, weight loss and a fine tremor has a normal thyroid gland on examination and normal radioiodine uptake in the neck. She is found to have a 6 cm right ovarian mass. TSH is suppressed. What is the most likely diagnosis?

• A Struma ovarii ✓
• B Granulosa cell tumour secreting ectopic TSH
• C Hydatidiform mole with thyrotoxicosis
• D Papillary carcinoma metastatic to the ovary

Explanation

Struma ovarii is a monodermal teratoma in which more than 50 percent of the tissue is functioning thyroid tissue, and it can secrete sufficient thyroid hormone to cause thyrotoxicosis while the neck shows absent radioiodine uptake because iodine is trapped in the pelvic tumour. Molar thyrotoxicosis occurs in pregnancy with a positive beta-hCG, which does not fit this profile.

Reference: Shaw's Textbook of Gynaecology, 17th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.