原发性纵隔卵黄囊瘤影像学表现

Imaging findings of primary mediastinal yolk sac tumors

目的探讨原发性纵隔卵黄囊瘤(PMYST)的CT、PET/CT表现。方法回顾性分析14例经病理确诊的PMYST患者的CT、PET/CT表现及临床资料,14例均接受胸部CT平扫及增强检查,7例同时接受PET/CT检查。结果14例病灶CT均表现为类圆形或分叶状肿块,最大径4.10~13.50 cm,平均(10.65±2.27)cm,其中13例(13/14,92.86%)最大直径均≥10.00 cm;CT平扫密度不均匀,增强扫描均表现为多发条形、细线状分隔样强化灶及片状无强化区,中度强化11例(11/14,78.57%),轻度强化3例(3/14,21.43%)。5例(5/14,35.71%)病变累及心包,3例(3/14,21.43%)累及左侧头臂静脉和/或上腔静脉、1例(1/14,7.14%)累及右中上肺。3例(3/14,21.43%)伴右肺门及纵隔淋巴结转移,右侧胸膜转移、右下肺转移各1例(1/14,7.14%),心包积液、胸腔积液各7例(7/14,50.00%)。7例病灶放射性摄取均明显增高。治疗后9例(9/14,64.29%)病情稳定或完全缓解,5例(5/14,35.71%)病情进展或术后复发。结论PMYST影像学主要表现为前纵隔巨大类圆形或分叶状密度不均匀肿块,常侵及周围血管及组织、脏器,多伴淋巴结及远处转移;增强扫描呈多发条形、线状分隔样强化灶及片状无强化区是其较为特征性的表现;病灶18 F-FDG摄取明显高代谢。

Objective To explore CT and PET/CT features of primary mediastinal yolk sac tumor(PMYST).Methods CT,PET/CT and clinical data of 14 patients with PMYST confirmed by percutaneous biopsy were retrospectively analyzed.All patients underwent plain scan and enhanced chest CT examination,while 7 patients underwent PET/CT examination.Results CT showed round or lobulated masses in all 14 cases.The maximum diameter of masses was 4.10—13.50 cm,with an average of(10.65±2.27)cm.Lesions with the maximum diameter≥10.00 cm were in 13 cases(13/14,92.86%).Plain CT showed non-uniform density or heterogeneous density,and the enhanced CT showed multiple strip,thin linear partition enhanced focus and flake non-enhanced area in 14 cases,among which moderate and mild enhancement were observed in 11 cases(11/14,78.57%)and 3 cases(3/14,21.43%),respectively.Cardiac envelope involvement was found in 5 cases(5/14,35.71%),left cephalobrachial vein and/or superior vena cava involvement were detected in 3 cases(3/14,21.43%),while the right upper and middle lobe involvement was noticed in 1 case(1/14,7.14%).There were 3 patients(3/14,21.43%)with right hilar and mediastinal lymph node metastasis,1(1/14,7.14%)with right pleural metastasis and 1(1/14,7.14%)with right lower lung metastasis.Pericardial effusion(7/14,50.00%)and pleural effusion(7/14,50.00%)were found each in 7 cases,respectively.PET/CT showed markedly increased radioactivity uptake in all 7 cases.During following-up after treatment,stable or recovered well after operation were observed in 9 cases(9/14,64.29%),whereas progressive or recurred after operation in 5 cases(5/14,35.71%).Conclusion The main imaging manifestations of PMYST include large round or lobulated non-uniform mass in the anterior mediastinum,often invading surrounding vessels,tissue and organs,mostly with lymph nodes and distant metastasis.The specific manifestations of PMYST are multiple strip-like,linear septate-like enhancement foci and patchy non-enhancement areas in enhanced CT.18 F-FDG uptake of the lesions are markedly hypermetabolic.