Proliferative Highly Differentiated Follicular Carcinoma Of Ovarian Origin (Hdfco) Presenting Long After Bilateral Oophorectomy

ABSTRACT Objective: The malignant spread of histologically benign struma ovarii was historically referred to as peritoneal strumosis. Recently, highly differentiated follicular carcinoma of ovarian origin (HDFCO) was proposed as a more accurate diagnostic term for this rare disease. We report the unusual case presentation of a woman with HDFCO and the subsequent management of her cancer. Methods: Her interventions included abdominal surgery, postoperative laboratory tests, imaging, thyroidectomy, radioactive iodine-123 (RAI-123) diagnostic screening, and thyroid function studies. Results: A 72-year-old Chinese female was diagnosed with metastatic HDFCO approximately 30 years after hysterectomy and bilateral oophorectomy. While undergoing evaluation for an upper gastrointestinal bleed, a computed tomography scan revealed a 10 cm pelvic mass and multiple other peritoneal tumors. She underwent tumor debulking surgery, and the pathology was interpreted at two institutions; both made the diagnosis of a very well-differentiated follicular carcinoma arising in struma ovarii. Lab tests revealed hyperthyroidism and RAI-123 uptake confirmed tumor production of thyroid hormone. A total thyroidectomy was performed in anticipation of treatment with radioactive iodine-131 (RAI-131). However, the patient remained clinically asymptomatic and, therefore, neither additional tumor debulking nor RAI-131 treatment were performed. No disease progression has been noted for over 3 years. Conclusion: This case highlights the potentially slow-growing nature of HDFCO which, in such cases, may be suited to less aggressive disease management. Abbreviations: CT computed tomography; Hb hemoglobin; HDFCO highly differentiated follicular carcinoma of ovarian origin; RAI-123 radioactive iodine-123; RAI-131 radioactive iodine-131; T3 triiodothyronine; T4 thyroxine; TSH thyroid-stimulating hormone;