Complete remission of peritoneal strumosis from struma ovarii after radioiodine therapy: a case report

Abstract

Background: Struma ovarii (SO) is a specialized monodermal teratoma composed predominantly of thyroid tissue (≥ 50%) and accounts for approximately 5% of all ovarian teratomas. In rare cases, the benign SO may spread to the peritoneal cavity and exhibit the histological features of struma ovarii in a condition termed peritoneal strumosis. Here, we present a rare case of complete remission of peritoneal strumosis from SO after radioiodine therapy.

Case presentation: A 41-year-old Chinese woman underwent transabdominal left oophorectomy for a benign SO 18 years prior to presentation in the clinic. She was admitted to our institution for periodic medical examination after ultrasonography revealed a left pelvic mass. The patient underwent total abdominal hysterectomy, right salpingo-oophorectomy, and omentectomy, and multiple biopsies were taken from the omentum and mesentery. Pathology revealed peritoneal strumosis without evidence of malignancy from SO. Afterward, a total thyroidectomy was performed, and a histological examination revealed multinodular goiter. In total, 4400 MBq of 131I was administered, and lesion remission was confirmed. Finally, after 1 year of follow-up, the patient had no evidence of recurrence.

Conclusion: Peritoneal strumosis from OS is a rare aggressive clinical manifestation that differs from malignancy. Conservative surgery with personalized radioiodine may be a practical therapeutic option for unresectable peritoneal strumosis, and long-term monitoring is recommended.

Keywords: Peritoneal strumosis; Radioiodine; Struma ovarii.

Fig. 1

CT examination revealed multiple seedings of nodules (red arrows) in the abdominopelvic cavity (A-C: nonenhanced CT; D-E: enhanced CT; F: coronal reformatted CT)

Fig. 2

Ultrasonography of the thyroid gland shows no nodular disease (A). Ultrasound images show a mass of approximately 2.8 × 2.2 × 2.6 cm with hyperechogenicity in the left posterior wall of the uterus (B). HE staining confirmed the diagnosis of peritoneal strumosis that extensively involved the left posterior wall of the uterus (C, magnification×5) and the peritoneum (D, magnification×10), with positive expression of CK19 (E, magnification×10) and galectin-3 (F, magnification×10)

Fig. 3

Posttherapy 131I whole-body image (A) revealing multiple intense iodine-avid lesions in the abdominopelvic cavity and thyroid bed. Abdominal CT (B, C; red arrows) and fused SPECT/CT (D, E; red arrows) revealed multiple nodules with hypermetabolic lesions in the liver capsule and left paracolic sulcus. Nine months later, a diagnostic 131I whole-body image (F) revealed complete resolution of all 131I foci previously noted. Abdominal CT (G, H; red arrows) and fused SPECT/CT (I, J; red arrows) confirmed that there was no evidence of residual disease