From the Guidelines
For poorly differentiated thyroid cancer arising from a mature cystic teratoma with a normal thyroid ultrasound, the next steps should prioritize a comprehensive and cautious approach.
Initial Management
First, it is recommended to conduct a thorough surgical resection of the teratoma and any involved structures, ensuring complete removal of the tumor, as suggested by the guidelines for the management of differentiated thyroid cancer 1.
Post-Operative Care
Post-operatively, consider administering TSH-suppressive therapy with levothyroxine (starting dose 100-200 mcg daily, titrating to achieve a TSH level between 0.1-0.5 mU/L) to reduce the risk of recurrence, in line with the recommendations for the management of differentiated thyroid cancer 1.
Additional Therapies
Additionally, a radioactive iodine scan and ablation (with 100-200 mCi of I-131) should be considered to eliminate any potential microscopic disease, as outlined in the guidelines for the management of differentiated thyroid cancer 1, followed by regular surveillance with:
- Thyroglobulin levels: to monitor for recurrence or metastasis, with highly sensitive assays of basal thyroglobulin used in lieu of TSH-stimulated thyroglobulin to verify the absence of disease 1.
- Periodic imaging studies: such as neck ultrasound, CT scans, to monitor for recurrence or metastasis, with neck US being the most effective tool for detecting structural disease in the neck 1.
Follow-Up
Regular follow-up with an endocrinologist and a multidisciplinary tumor board is crucial to adjust the treatment plan as necessary and ensure optimal management of the patient's condition, taking into account the diagnostic criteria for poorly differentiated carcinomas and the molecular profiling of the tumor 1.
Some key points to consider in the management of poorly differentiated thyroid cancer include:
- The diagnostic criteria for poorly differentiated carcinomas, which include a solid/trabecular/insular growth pattern plus at least one of the following: mitotic index 3 per 10 high-power fields, necrosis, or convoluted nuclei 1.
- The molecular profiling of the tumor, which can distinguish two major classes of PTCs characterized by BRAF-predominant and RAS-predominant molecular signatures 1.
From the Research
Next Steps for Poorly Differentiated Thyroid Cancer
Arising from a Mature Cystic Teratoma (MCT) with a Normal Thyroid Ultrasound
- The presence of poorly differentiated thyroid cancer in a mature cystic teratoma is rare and often found incidentally on surgical pathology specimens 2, 3.
- For patients with poorly differentiated thyroid cancer, assessing the risk of cancer-related death and recurrence is crucial for clinicians 4.
- The Turin consensus remains the mainstay diagnostic criteria for poorly differentiated thyroid carcinoma, and individualized assessments are decisive for treatment options 5.
- Treatment options for poorly differentiated thyroid cancer include complete resection, adjuvant therapies such as 131I therapy, external beam radiation therapy, and chemotherapy, as well as emerging therapeutics like molecular targeted therapy, differentiation therapy, and immunotherapy 5, 6.
- Considering the aggressive nature of poorly differentiated thyroid cancer, aggressive treatment may be necessary, and 131I therapy should be considered in all patients postoperatively 6.
- External beam radiotherapy may be considered in patients with T3 tumors without distant metastasis, T4 tumors, or regional lymph node involvement 6.
- Regular follow-up of thyroid image and data is necessary to monitor the patient's condition and adjust treatment plans as needed 3.