Endocrine Abstracts

Introduction

Papillary thyroid cancer (PTC) has generally good prognosis irrespective of lymph node metastases. The rate of survival in patients with distant metastases is variable, depending upon the site of metastases and radioiodine accumulation status. The median survival of patients with brain metastases is approximately one year.

Case

We present a 66 years old woman with a tumour triplicity (PTC, breast cancer and ovarian cancer). She underwent total thyroidectomy (T1bmN1bM0, stage IV A) in 2013. Radioiodine was administered twice with a cumulative dose of 7.4 GBq (300 mCi) 131-I. The other tumours were in remission. Since May 2018 there was a slight increase of thyroglobulin (0.52 µg/l). In December 2018 the thyroglobulin level was 2.24 µg/l and the ultrasound of the neck was negative. She was treated with radioiodine (100 mCi) with a negative post-radioiodine whole-body scan. During next follow-up there was further increase of thyroglobulin level (6.53 µg/l). CT scan of the whole body provided a negative result. After two months she was examined for malaise, vertigo and left hemiparesis. Brain MRI showed a solitary tumour of the frontal lobe 25 × 26 × 26 mm. The thyroglobulin level was 12.56 µg/l at that time. Extirpation of the tumour confirmed metastases of PTC. Follow-up MRI of the brain was without any residual tumour. She was treated with radioiodine (150 mCi) after administration of recombinant human TSH. The patient, two years after operation, has a stable level of thyroglobulin (0.94 µg/l), with negative brain MRI and whole-body FDG-PET scan.

Conclusion

Brain metastases of papillary thyroid cancer are very rare. Surprisingly our patient had only mild increases of thyroglobulin level, that did not allow us, in the beginning, to suspect possible brain metastases. We diagnosed the metastases only after the patient started to have neurological symptoms. There are no guidelines for the treatment of brain metastases from the thyroid cancer. Surgical resection is probably associated with prolonged survival but till now there is no evidence of survival benefit from radioiodine therapy.