Endocrine Abstracts

Introduction: Differentiated thyroid cancer has usually good prognosis and long-term survival. Distant metastasis ratio is 5–15%. Metastasis to cerebrum, breast, liver, kidney, muscle, and skin is relatively rare. The study of molecular mechanisms of PTC has demonstrated that BRAFV600E gene mutation is a significant event in the process of this disease.

Case: 55-year-old-male patient who had multinodular goiter showed malignant cytology in fine-needle-biopsy. Total thyroidectomy, neck dissection were performed. Pathology was consistent with PTC, diameter was 4.5 cm with vascular and perineural invasion, 11/13 lymph nodes had PTC infiltration. Bilateral cervical, mediastinal lymph node, bilateral multiple areas in lung, C4-C5 vertebrae had increased FDG uptake in PET/CT after surgery. Second-look neck dissection was performed. 33/46 lymph nodes had PTC infiltration. 200 mCi of RAI ablation therapy was given [TSH: 82 μIU/ml (0.34–5.6), thyroglobulin: 38 817 ng/ml (1.15-35), anti-thyroglobulin:107 IU/ml (0-115)]. On whole body scanning (WBS), radioactivity was detected in neck, mediastinum and both lungs. Because of high thyroglobulin levels, RAI ablation treatment with the dose of 250 mCi was planned after one year of first ablation. On WBS, radioactivity was detected in region of mediastinal, axillary, hemithoraxes and liver. Patient did not come to follow up for one year, then he admitted to emergency department with headache and vomiting. 37×47 mm mass with solid-cystic components in right side of cerebellum was detected in cranial-MRI. Patient was referred to neurosurgery clinic. There were multiple lymph nodes with pathological dimension in both axillary and mediastinal areas and multiple metastatic foci existed in bilateral lower lungs, in liver and 8×5 cm in left, 3.5×2.5 cm in right adrenal glands were consistent with metastases in CT. Cerebellar mass was excised. PTC infiltration was reported and BRAF V600E mutation was analyzed in cerebellar metastatic mass.

Conclusion: BRAFV600E mutations in PTC are associated with extrathyroidal spread, lymph node metastasis, tumor recurrence and mortality.