[Cystic papillary carcinoma of the thyroid--sonographic-pathologic correlation]

Ultrasonographic findings of 13 patients with cystic papillary carcinoma (CPC) of the thyroid gland were reviewed retrospectively correlating with pathologic findings. A 4-6 cm oval cystic structure with a 2-3 cm pedunculated projection of mass into the lumen was the characteristic sonographic findings of CPC. However, other sonographic findings of CPC simulated adenoma, nodular goiter or follicular carcinoma. Pathological investigation revealed that malignant cells tended more to be located in intracystic pedunculated mass and/or pericystic region than in the cyst wall. In most of the cases cyst walls were chiefly composed of granulomatous tissue with scattered malignant cells. These findings indicate that the needle biopsy should be done under ultrasonographic guidance to obtain sufficient material for accurate cytologic and/or pathologic diagnosis, thereby reducing the number of false negative cases.