Pituitary metastasis of follicular thyroid carcinoma.

Objective: The case of a 60-year-old male patient with follicular thyroid cancer who developed a pituitary mass proved to be a metastasis from thyroid cancer.

Methods: Assessment with whole-body scan, ultrasound, computed tomography and thyroglobulin measurements.

Results: Despite surgery and repeated doses of radioiodine, the patient developed diplopia and ptosis of the right eyelid, along with increasing thyroglobulin levels. A pituitary mass was discovered, with no signs of pituitary deficiency. The mass was removed and found to consist of neoplastic cells immunohistochemically positive to thyroglobulin.

Conclusions: Distant metastases may develop in cases of follicular thyroid carcinoma, even after repeated doses of (131)I. Metastatic follicular thyroid carcinoma to the pituitary is a rare entity.