46例甲状腺微小乳头状癌的CT征象分析

CT analysis of 46 cases of papillary thyroid microcarcinoma

关键词:  甲状腺癌  微小乳头状癌  淋巴结转移  X线计算机体层摄影术

Key words:  thyroid carcinoma  papillary microcarcinoma  lymphatic metastasis  X-ray computed tomography

摘要:

目的　探讨甲状腺微小乳头状癌的CT征象，提高对CT诊断的认识。方法　对46例CT平扫和（或）双期增强扫描可见显示，且经手术病理证实的55个甲状腺微小乳头状癌病灶的CT表现进行回顾性分析，总结其CT表现特点。 结果　（1）46例共55个癌灶：其中38例单发癌灶，7例双侧发生，1例单侧双发。（2）38个癌灶边缘模糊，9个侵犯甲状腺被膜，2个侵犯前方肌肉。（3）16个癌灶内见钙化灶，13个有微钙化。（4）9个癌灶CT平扫未见显示。（5）增强扫描后38个癌灶明显强化，37个低于正常甲状腺组织，18个中央见结节样强化，周围密度略低。32个病灶增强后显示病灶小于平扫。（6）21例伴颈部淋巴结转移。结论　甲状腺微小癌的CT表现具有一定的特征：平扫病灶边缘模糊，易侵犯甲状腺被膜，多伴有微钙化，增强扫描强化明显,但低于邻近正常甲状腺组织，可能出现中央明显强化结节，增强后病灶范围多小于平扫低密度范围，且可能多发小癌灶并存，常常伴发下颈部淋巴结转移，这些特征有助于甲状腺微小癌的诊断和鉴别诊断。

Abstract:

Objective To investigate the manifestations on CT images of papillary thyroid microcarcinoma (PTMC), and improve the diagnostic level of CT on PTMC. Methods Totally 46 patients, who had CT scan and pathologically proven PTMC, were retrospectively analyzed. All cases were shown to have cancer on non-enhanced (NECT) and/ or contrast enhanced CT (CECT) images. Results (1) 55 foci of carcinoma in 46 cases: single focus in 38 cases, bilateral foci in 7 cases, and unilateral multiple foci in 1 case. (2) 38 foci had blurred margin and two had anterior muscle invasion. (3) Calcification was seen in 16 foci, micro-calcification in 13 foci. (4) 9 foci were not seen in NECT. (5) 38 foci showed marked enhancement on CECT. 37 foci had lower density compare to thyroid gland. 18 foci were enhanced with nodular enhancement in the center and low density area in periphery. 32 foci were smaller on CECT than on NECT (6) Cervical lymph nodes metastasis was found in 21 cases. Conclusion PTMCs have certain features on CT, which may be helpful in the diagnosis and differentiation of PTMC. The margin of lesions on NECT is blurred. The capsule of thyroid gland is easily to be infiltrated. Micro-calcification is commonly seen in PTMC. Most foci are strongly enhanced on CECT, but the density is lower than normal thyroid gland. Strongly enhanced nodules in the center may be seen. The PTMCs are usually looked like smaller on CECT than on NECT. Multifocality and lymph node metastasis of lower neck are very common.