M L GildCancer Genetics, Kolling Institute of Medical Research, Sydney, New South Wales, Australia Faculty of Medicine, University of Sydney, Sydney, New South Wales, Australia Department of Endocrinology and Diabetes, Royal North Shore Hospital, Sydney, New South Wales, Australia
R J Clifton-BlighCancer Genetics, Kolling Institute of Medical Research, Sydney, New South Wales, Australia Faculty of Medicine, University of Sydney, Sydney, New South Wales, Australia Department of Endocrinology and Diabetes, Royal North Shore Hospital, Sydney, New South Wales, Australia
B G RobinsonCancer Genetics, Kolling Institute of Medical Research, Sydney, New South Wales, Australia Faculty of Medicine, University of Sydney, Sydney, New South Wales, Australia Department of Endocrinology and Diabetes, Royal North Shore Hospital, Sydney, New South Wales, Australia
Struma ovarii is a rare, usually benign ovarian tumour with malignancy occurring in <5% of cases. Metastases, particularly seeding to bone, are extremely rare. Presentation is variable but often features local pain and/or ascites and hyperthyroidism may occur. It is not established how to best treat and follow patients with extensive disease. Case reports of radioiodine (I131) ablative therapy following thyroidectomy have shown reduced recurrence. We describe the case of a 33-year-old woman who presented with bone pain and was diagnosed with skeletal metastases with features of follicular thyroid carcinoma. However, thyroid pathology was benign. She recalled that 5 years prior, an ovarian teratoma was excised, classified at that time as a dermoid cyst. Retrospective review of this pathology confirmed struma ovarii without obvious malignant features. The patient was found to have widespread metastases to bone and viscera and her thyroglobulin was >3000 µg/L following recombinant TSH administration prior to her first dose of I131. At 25 months following radioiodine treatment, she is in remission with an undetectable thyroglobulin and clear I131 surveillance scans. This case demonstrates an unusual presentation of malignant struma ovarii together with challenges of predicting metastatic disease, and demonstrates a successful radioiodine regimen inducing remission.
Malignant transformation of struma ovarii (MSO) is extremely rare and even rarer are metastatic deposits in bone and viscera.
MSO can be difficult to predict by initial ovarian pathology, analogous to the difficulty in some cases of differentiating between follicular thyroid adenoma and carcinoma.
No consensus exists on the management for post operative treatment of MSO; however, in this case, three doses of 6Gbq radioiodine therapy over a short time period eliminated metastases to viscera and bone.
Patients should continue to have TSH suppression for ~5 years.
Monitoring thyroglobulin levels can predict recurrence.
A case of follicular thyroid cancer with intense focal Methionine uptake on 11C-Methionine PET/CT is reported here. The use of 11C-Methionine PET in differentiated thyroid cancer is currently being investigated as a surrogate tracer compared to the more widely used 18F-FDG PET. This case illustrates the potential incremental value of this modality, not only in the localizing of parathyroid adenoma, but also indicating that 11C-Methionine PET might have a potential of increasing the pretest likelihood of thyroid malignancy in a cold nodule with highly increased Sestamibi uptake.
11C-Methionine PET/CT and 18F-Fluorocholine PET/CT often visualizes the parathyroid adenoma in case of negative Tc-99m-MIBI SPECT/CT.
A cold nodule in Tc-99m Pertechnetat thyroid scintigraphy with a negative Sestamibi scintigraphy has a very low probability of being malignant.
However, the pretest likelihood of thyroid cancer in a cold nodule with increased Sestamibi uptake is low.
11C-Methionine PET might have a potential incremental value in increasing the pretest likelihood of thyroid malignancy in a cold nodule with highly increased Sestamibi uptake.
We report a patient with Graves’ disease who remained persistently hyperthyroid after a total thyroidectomy and also developed de novo Graves’ ophthalmopathy 5 months after surgery. She was subsequently found to have a mature cystic teratoma containing struma ovarii after undergoing a total hysterectomy and salpingo-oophorectomy for an incidental ovarian lesion.
It is important to investigate for other causes of primary hyperthyroidism when thyrotoxicosis persists after total thyroidectomy.
TSH receptor antibody may persist after total thyroidectomy and may potentially contribute to the development of de novo Graves’ ophthalmopathy.
Struma ovarii is a rare ovarian teratoma characterized by the presence of thyroid tissue as the major component. Malignant transformation of the thyroidal component (malignant struma ovarii) has been reported in approximately 5% of struma ovarii. The management and follow-up of this unusual disease remain controversial. We report the case of a woman with a history of autoimmune thyroiditis and a previous resection of a benign struma ovarii that underwent hystero-annexiectomy for malignant struma ovarii with multiple papillary thyroid cancer foci and peritoneal involvement. Total thyroidectomy and subsequent radioiodine treatment lead to complete disease remission after 104 months of follow-up. The diagnosis and natural progression of malignant struma ovarii are difficult to discern, and relapses can occur several years after diagnosis. A multidisciplinary approach is mandatory; after surgical excision of malignant struma, thyroidectomy in combination with 131I therapy should be considered after risk stratification in accordance with a standard approach in differentiated thyroid cancer patients.
Malignant struma ovarii is a rare disease; diagnosis is difficult and management is not well defined.
Predominant sites of metastasis are adjacent pelvic structures.
Thyroidectomy and 131I therapy should be considered after risk stratification in accordance with standard approaches in DTC patients.