Metastatic malignant struma ovarii: a case report and review of the literature on the management of malignant struma ovarii.

OBJECTIVES: To present a case of metastatic struma ovarii, to review the literature on malignant struma ovarii and to discuss the management in locoregional and metastatic disease. METHODS: We present a case of an 82-year-old patient with a malignant struma ovarii and liver metastasis. The patient was treated with pelvic surgery, total thyroidectomy, radioactive iodine therapy and TSH suppression therapy with levothyroxine. We performed a PubMed search for case reports of metastatic struma ovarii. RESULTS: 43 cases of metastatic struma ovarii were identified. 53.5% of patients presented with metastatic disease at diagnosis. Mean time to development of metastasis was 6.9 years in the group with initial locoregional disease. First-line treatment was pelvic surgery in all patients. Thyroidectomy was performed in 83.7% of patients, subsequent radioactive iodine therapy in 79.1%, followed by TSH suppression therapy in 46.5% of patients. Mean time of follow-up after diagnosis of metastases was 3.6 years, ranging from 0.5 to 24 years. At the end of the follow-up, 51.1% of patients were free of disease, 34.9% were alive with disease, 7.0% died of disease and 7.0% were lost to follow-up. CONCLUSION: The majority of patients with metastatic struma ovarii were treated with pelvic surgery, total thyroidectomy and radioactive iodine therapy. Suppression of TSH with levothyroxine was given in less than half of the patients. In non-metastatic setting, the same approach could be considered depending on the patient profile.

Standardization of Free Thyroxine Measurements Allows the Adoption of a More Uniform Reference Interval.

BACKGROUND: The IFCC Committee for Standardization of Thyroid Function Tests intended to standardize free thyroxine (FT4) immunoassays. We developed a Système International d'Unités traceable conventional reference measurement procedure (RMP) based on equilibrium dialysis and mass spectrometry. We describe here the latest studies intended to recalibrate against the RMP and supply a proof of concept, which should allow continued standardization efforts. METHODS: We used the RMP to target the standardization and reference interval (RI) panels, which were also measured by 13 manufacturers. We validated the suitability of the recalibrated results to meet specifications for bias (3.3%) and total error (8.0%) determined from biological variation. However, because these specifications were stringent, we expanded them to 10% and 13%, respectively. The results for the RI panel were reported as if the assays were recalibrated. We estimated all but 1 RI using parametric statistical procedures and hypothesized that the RI determined by the RMP was suitable for use by the recalibrated assays. RESULTS: Twelve of 13 recalibrated assays had a bias, meeting the 10% specification with 95% confidence; for 7 assays, this applied even for the 3.3% specification. Only 1 assay met the 13% total error specification. Recalibration reduced the CV of the assay means for the standardization panel from 13% to 5%. The proof-of-concept study confirmed our hypothesis regarding the RI but within constraints. CONCLUSIONS: Recalibration to the RMP significantly reduced the FT4 immunoassays' bias, so that the RI determined by the RMP was suitable for common use within a margin of 12.5%.

Harmonization of Serum Thyroid-Stimulating Hormone Measurements Paves the Way for the Adoption of a More Uniform Reference Interval.

BACKGROUND: The IFCC Committee for Standardization of Thyroid Function Tests developed a global harmonization approach for thyroid-stimulating hormone measurements. It is based on a multiassay method comparison study with clinical serum samples and target setting with a robust factor analysis method. Here we describe the Phase IV method comparison and reference interval (RI) studies conducted with the objective to recalibrate the participating assays and demonstrate the proof-of-concept. METHODS: Fourteen manufacturers measured the harmonization and RI panel; 4 of them quantified the harmonization and first follow-up panel in parallel. All recalibrated their assays to the statistically inferred targets. For validation, we used desirable specifications from the biological variation for the bias and total error (TE). The RI measurements were done with the assays' current calibrators, but data were also reported after transformation to the new calibration status. We estimated the pre- and postrecalibration RIs with a nonparametric bootstrap procedure. RESULTS: After recalibration, 14 of 15 assays met the bias specification with 95% confidence; 8 assays complied with the TE specification. The CV of the assay means for the harmonization panel was reduced from 9.5% to 4.2%. The RI study showed improved uniformity after recalibration: the ranges (i.e., maximum differences) exhibited by the assay-specific 2.5th, 50th, and 97.5th percentile estimates were reduced from 0.27, 0.89, and 2.13 mIU/L to 0.12, 0.29, and 0.77 mIU/L. CONCLUSIONS: We showed that harmonization increased the agreement of results from the participating immunoassays, and may allow them to adopt a more uniform RI in the future.