胸腺原发不典型类癌影像学表现

Imaging manifestations of primary thymic atypical carcinoid

目的观察胸腺原发不典型类癌(pTAC)的影像学表现。方法回顾性分析经病理证实的8例pTAC胸部CT和MRI资料,观察其影像学表现。结果8例pTAC均为前纵隔单发病灶,5个位于偏右、3个偏左,最大径3.5~16.0 cm、中位最大径8.3 cm;7个呈团块状、1个呈分叶状,边界均清晰;CT均表现为不均匀软组织密度影,内见囊变和坏死,2个内见钙化;MR T1WI均呈等信号,T2WI均呈高信号,弥散加权成像见弥散受限,表观弥散系数(ADC)0.23×10^(-3)~1.12×1^(0-3)mm^(2)/s,中位ADC为0.64×10^(-3)mm^(2)/s;增强后7个病灶不均匀中度强化、1个不均匀轻度强化;4个见瘤内血管。8例中,3例胸腔积液、3例心包积液,5例纵隔淋巴结转移合并或不合并颈部、锁骨上淋巴结转移,4例胸膜转移,4例骨转移(累及邻近肋骨及颈、胸椎),1例肝转移。结论pTAC影像学表现具有一定特征性,有助于诊断及鉴别诊断。

Objective To observe imaging manifestations of primary thymic atypical carcinoid(pTAC).Methods Chest CT and MRI data of 8 patients with pTAC confirmed pathologically were retrospectively analyzed,and imaging manifestations of pTAC were observed.Results pTAC present as single anterior mediastinum lesion in all 8 cases,5 located on the right side and 3 on the left side of anterior mediastinum,with the maximum diameter of 3.5 to 16.0 cm and a median maximum diameter of 8.3 cm,7 were clump-shaped and 1 was lobed,all with clear boundaries.CT showed uneven soft tissue densities with cystic areas and necrosis,and calcifications were noticed in 2 lesions.The lesions showed iso-signals on T1WI and high signals on T2WI,with restricted diffusion on diffusion weighted imaging,the apparent diffusion coefficient(ADC)ranged from 0.23×10^(-3) to 1.12×10^(-3) mm^(2)/s,with a median ADC of 0.64×10^(-3) mm^(2)/s.On enhanced CT and MRI,moderate uneven enhancement was found in 7 lesions,while mild uneven enhancement was observed in one lesion,4 with intratumoral vessels.Among 8 cases,pleural effusion and pericardial effusion were detected each in 3 cases,lymph node metastases of mediastinum with or without neck,supraclavicular areas were found in 5 cases,while pleural metastases and bone metastases(involving adjacent ribs,cervical and thoracic vertebrae)were noticed each in 4 cases,and liver metastases was detected in 1 case.Conclusion Imaging manifestations of pTAC had certain characteristic,being helpful to diagnosis and differential diagnosis.