CT features of primary thyroid malignant lymphoma        WANG Zhi-hong，DONG Wen-wu，HE Liang，et al. Department of General Surgery，the First Hospital，China Medical University，Shenyang 110001，China
Corresponding author: ZHANG Hao, E-mail：haozhang@mail.cmu.edu.cn
Abstract    Objective    To evaluate the CT features of primary thyroid malignant lymphoma (PTML). Methods    The CT features of 14 cases of PTML admitted between January 2000 and June 2011 at the First Hospital of China Medical University were analyzed retrospectively and compared with surgical and pathological results. Results    The common CT appearances were that the density of the enlarged thyroid mass was lower than that of the muscle nearby, unconspicuous enhancement in contrast-enhanced CT scan and calcification and necrosis were rare. The CT features were classified into three types：3 cases of solitary nodule (type 1)，which was a solitary nodule surrounded by normal thyroid tissue；8 cases of massive mass (type 2)，which were usually in homogeneous hypodense with integrated capsule；and 3 cases of pervasive mass (type 3)，which were manifested as unconspicuous enhancement mass with narrow cordlike hyperdense thyroid tissue around or inside in it. Conclusion    The CT appearance of PTML is usually manifested as massive type. The pervasive type has its characteristic. The CT features combine with the history of rapidly growing thyroid mass and the increased thyroid antibody titer are helpful for preoperative diagnosis.