Struma ovarii presenting with Hashimoto's thyroiditis: a case report

Area of Science:

• Endocrinology
• Gynecologic Pathology

Background:

• Struma ovarii, a rare germ cell tumor containing thyroid tissue, can lead to thyrotoxicosis.
• Co-existing autoimmune thyroid disorders can complicate diagnosis and management.
• Ectopic thyroid tissue within an ovarian teratoma can present unique clinical challenges.

Purpose of the Study:

• To describe an unusual case of struma ovarii associated with lymphocytic thyroiditis.
• To highlight a rare presentation of subclinical hyperthyroidism originating from ectopic thyroid tissue.
• To discuss diagnostic and management considerations for struma ovarii with concurrent thyroid pathology.

Main Methods:

• Case report of a 17-year-old female with a history of ovariectomy for struma ovarii.
• Evaluation included laboratory tests, radioiodine uptake, abdominal MRI, iodine-131 whole body scanning, and thyroid ultrasonography.
• Histopathological analysis of ectopic thyroid tissue was performed.

Main Results:

• The patient presented with persistent subclinical hyperthyroidism and low radioiodine uptake post-ovariectomy.
• Imaging studies ruled out residual or recurrent struma ovarii.
• Laboratory and histopathological findings indicated Hashimoto's thyroiditis as the cause of thyrotoxicosis in the ectopic thyroid tissue.

Conclusions:

• Struma ovarii is an uncommon cause of thyrotoxicosis, particularly when complicated by other thyroid conditions.
• Diagnosis can be challenging, necessitating consideration of autoimmune thyroiditis in the differential.
• Management strategies for struma ovarii require further consensus, especially regarding residual disease and metastasis.