[Cystic thyroid masses: ultrasonographic and pathologic correlation]

Forty-nine patients with 63 cystic thyroid masses who had undergone preoperative sonography were retrospectively reviewed. 52 lesions (83%) were benign and others (17%) were malignant. Among various sonographic findings of cystic thyroid masses, oval cystic lesions with polyp or dome like solid component projecting into the lumen were all diagnosed adenomatous goiter. Irregular cystic structures with more than 2 cm finger like pedunculated mass extended into and/or out of the lumen were all diagnosed papillary carcinoma. Small oval cysts (less than or equal to 1 cm) with strong echo were all diagnosed colloid goiter. The other sonographic type of cystic thyroid masses had somewhat malignancy (12-30%), not having characteristics which differentiate benign from malignant lesions. Pathologic findings of malignant lesions showed that cancer cells existed rather in pericystic portion than in cyst wall except for finger like solid component projecting into the lumen which was papillary carcinoma itself. Ultrasonically guided needle biopsy should be performed to get samples of above portions.