Metastatic follicular struma ovarii complicating pregnancy: a case report and review of the literature

A 35-year-old woman was determined to have an ovarian cyst and underwent a right ovarian cystectomy at 10 weeks of gestation. A histopathological examination revealed follicular carcinoma arising in a teratoma. No evidence of metastasis was found after delivery. She underwent a total thyroidectomy, followed by radioactive iodine (RAI) therapy. However, her serum thyroglobulin level increased to 1,437 ng/ml (normal range: 0-52 ng/ml) after 10 months. Radioiodine scintigraphy and abdominal computed tomography revealed liver metastasis and peritoneal seeding. She underwent debulking surgery of the liver, right salpinx, and peritoneal seeding nodules. A pathological examination showed metastatic follicular carcinoma with focal poorly differentiated features. Adjuvant RAI therapy was restarted, and her serum thyroglobulin levels returned to normal. In conclusion, metastatic lesions were successfully treated with a combination of debulking surgery and RAI therapy. Close medical follow-up monitoring serum thyroglobulin levels is mandatory in such patients.