Endocrine Abstracts

Differentiated thyroid carcinoma (DTC) is the most frequent endocrine neoplasm. Follicular thyroid carcinoma (FTC) is the second histological variant in frequency after papillary thyroid carcinoma (PTC). Cerebellar metastases from DTC are extremely rare, corresponding about 1% of all cerebellar metastases, and being the majority metastases from PTC. To the best of our knowledge there have been no reported cerebellar metastases from CFT so far. We present here the first clinical case of cerebellar metastasis from FTC. She was a 78 year-old woman who underwent total thyroidectomy 23 years ago showing an atypical thyroid adenoma in the left thyroid lobe in the pathological study. She received radioiodine therapy in several occasions (total accumulated dose 704 mCi). A chest computed tomography (CT) performed 15 years later identified two lung nodules with cervical lymphadenopathies. Cervical ultrasound and fine-needle aspiration (FNA) was performed, showing reactive lymphadenitis. Serum thyroglobulin levels were increasing in subsequent medical visits (4.8 to 57.9 ng/ml). Thyroglobulin antibody levels were always negative. In the follow-up localizing study a whole body CT scan revealed stable pulmonary metastases and an image at the left cerebellar hemisphere level compatible with metastasis of 2×1.6 cm. The patient underwent surgery of the cerebellar lesion. Inmunohistochemical findings showed a thyroid origin of the metastatic lesion, with tumor cells with diffuse and intense positivity for cytokeratin 7 (CK7), thyroid transcription factor-1 (TTF-1) and thyroglobulin, focal and weak positivity for CK19, and negativity for PGAF, Galectin-3 and CK20. The analysis of V600K V600E BRAF gene mutations was negative. These findings support histological metastasis from FTC. In conclusion, we report the by first time a patient with cerebellar metastasis from FTC, who was successfully treated by surgical resection.