Malignant struma ovarii

Background A 25-year-old woman presented to her gynecologist with pelvic pain. Pelvic ultrasonography showed a 9 cm left ovarian mass. The patient underwent left oophorectomy, omental biopsy, and lymph no e sampling. The ovarian mass proved to be a struma ovarii with numerous microscopic foci of papillary thyroid carcinoma. The patient had no symptoms of hyperthyroidism, and her thyroid function and serum thyroglobulin levels were normal. Investigations Investigations included a pelvic ultrasound scan, histological examination of the ovarian mass and omental nodules, and lymph node sampling. Diagnosis Malignant struma ovarii. Management The patient was referred to an endocrinology clinic for further investigations. Serum levels of TSH, thyroglobulin and thyroglobulin antibodies were measured. In addition, the patient underwent thyroid ultrasonography, which showed a I cm nodule that proved benign on biopsy. She was treated with thyroxine to reduce TSH secretion. Follow-up pelvic ultrasonography I year later showed no evidence of recurrent disease, and her serum thyroglobulin levels remained normal.