Introduction: Thyroid tissue ectopically located in the ovary can be reported accidentally after adnexectomy, but as a primary cause of hyperthyroidism this diagnosis is rare. The clinical search for a functional ectopic thyroid tissue requires intense clinical focus and a multidisciplinary approach.
Case description: This case report demonstrates a patient with a history of Graves' disease who had undergone thyroidectomy combined with postoperative 131I radioablation. Despite the previous treatment, she developed an outburst of hyperthyroidism ten years later. Only very close follow-up enabled us to disclose the right condition. The ovarian source of thyroid hormone production was removed by laparoscopic adnexectomy and a right sided benign ovarian struma was confirmed.
Conclusion: Most patients treated by thyroidectomy and radioiodine do not require extended periods of follow-up or postoperative investigations, but when the clinical or laboratory signs change, clinicians should be prepared to perform the necessary re-evaluation in order to provide the best care.
Keywords: hyperthyroidism; ovarian goiter; struma ovarii; thyroidectomy.