Aggressive behavior of papillary microcarcinoma in a patient with Graves' disease initially presenting as cystic neck mass.

Prognosis of papillary carcinoma of the thyroid associated with Graves' disease is controversial; nevertheless, tumors smaller than 1 cm (microcarcinoma) are usually considered to render a good prognosis. We describe a patient with Graves' disease who developed a lateral cystic neck mass that was later confirmed to be a metastatic lymph node from papillary thyroid microcarcinoma. Contrary to having a good prognosis with a microcarcinoma, our patient developed bilateral lung metastases. The possible role of thyroid stimulating immunoglobulins in the aggressive course of the tumor is discussed.