Struma ovarii recurrence with peritoneal strumosis: A case report

Background: Malignant transformation of thyroid tissue in struma ovarii and metastasis are uncommon. Benign thyroid tissue may spread to the peritoneal cavity in rare cases, and pathologic examination of the peritoneal implants shows multiple nodules of varying sizes of mature thyroid tissue similar to struma ovarii. This condition is termed “peritoneal strumosis”. It is very rare and therefore, both the criteria for diagnosis and its management are under discussion. The recommended treatment of metastatic struma ovarii should contain, in addition to local resection of the extraovarian tumor, total thyroidectomy in conjunction with radioiodine scanning and radioiodine ablation. Case report: A 38 year-old woman had presented with benign struma ovarii 12 years previously. She was referred to our department because of a right ovarian tumor. After confirming the diagnoses of metastatic recurrent benign struma ovarii, we performed debulking surgery with the aim of resecting all tumor masses. The uterus, left adnexa, and pelvic peritoneum were surgically extracted “en bloc”. No macroscopic tumor was left post-operatively. The first post operative 123 I scintography with15 MBq iodine-123 one month post-operatively showed a small but suspicious focus in the front left perivesical pelvic area. In the ventral visual presentation multiple discrete foci, located in right perivesical, supravesical and in the ventral upper abdomen, were seen. We then referred the patient for thyroidectomy and radioiodine ablation. The following periodic follow-ups of the patient did not show any signs of recurrence or progression of the disease. Conclusion: Patient with benign metastatic struma ovarii (also known as Highly differentiated follicular carcinoma of ovarian origin - HDFCO) may affectively be treated with local resection of the extraovarian tumor and subsequent thyroidectomy followed by radioactive iodine ablation.