Abstract 38: Sellar mass – An unusual presentation of metastatic thyroid carcinoma

Background: Sellar metastases are rare. They may precede the diagnosis of primary malignancy in 20-30% of the cases. Case Report: A 47year female presented with ptosis and diminished vision of right eye. She had a mass in the sellar region extending into the suprasellar area. Her serum prolactin level was 215 ng/ml. She had galactorrhea, secondary hypothyroidism, secondary hypocortisolemia. A trial of cabergoline was given for 6 weeks. She had progressive diminution in vision and a repeat MRI brain showed an increase in the size of the mass. She underwent tumour decompression. The histopathology was suggestive of metastatic tumor of the sella. Immunohistochemistry of pituitary biopsy was positive for CK and TTF-1 (nuclear). On evaluation, FDG-PET CT scan showed metabolically active nodule in the left lobe of thyroid. Ultrasound scan of thyroid showed multinodular goiter (TIRADS 5). FNAC of the left thyroid nodule was suggestive of Hashimoto's thyroiditis. With a suspicion of primary thyroid malignancy, total thyroidectomy was performed. Surgical biopsy report of thyroid showed well-differentiated follicular carcinoma. Radioablation with I-131 was performed for residual thyroid tissue in the neck and metastases. Conclusion: Metastasis to the pituitary can be a rare presentation of thyroid cancer. It may mimic a pituitary adenoma.