Dual ectopic thyroid tissue with a eutopic thyroid gland: An unusual presentation of struma ovarii

ABSTRACT

Struma ovarii is an exceptionally rare monodermal ovarian teratoma characterized by the predominance of thyroid tissue and is frequently misdiagnosed due to its nonspecific clinical and radiological features. Preoperative differentiation from other ovarian neoplasms is challenging, and definitive diagnosis is usually established only on histopathological examination. We report a case of unilateral benign struma ovarii in a 19-year-old unmarried female, in which the tumor closely mimicked ovarian malignancy on imaging owing to its large size and complex morphology, despite normal tumor markers and thyroid function tests. The patient was successfully managed with fertility-preserving surgical excision. Postoperative endocrine assessment confirmed a normal eutopic thyroid gland and a coexisting thyroglossal duct cyst, representing a rare dual ectopic thyroid presentation in the presence of an intact orthotopic thyroid. This case highlights the diagnostic challenges of struma ovarii, particularly in young patients, and underscores the importance of histopathology in establishing the diagnosis. Surgical resection remains the cornerstone of treatment and is associated with an excellent prognosis in benign cases.