Parathyroid carcinoma: high-frequency sonographic features

The authors reviewed the features on high-frequency (10 MHz), realtime sonograms of parathyroid carcinoma in eight patients to identify characteristics that could preoperatively distinguish malignant from benign lesions. The mean diameter of the eight carcinomas was 2.4 cm. They were typically ovoid or round and had a lobulated contour. The carcinomas were predominantly hypoechoic relative to the adjacent thyroid, but two of the eight contained both hypoechoic and hyperechoic regions, and three contained cystic spaces. Two carcinomas were grossly invasive on ultrasonographic (US) examination, although seven were proved histologically to be invasive. High-resolution US provides a noninvasive means to localize primary and locally recurrent parathyroid carcinomas preoperatively but fails to distinguish carcinomas from large adenomas reliably, except in cases with extensive invasion of adjacent structures.