Mayhew J, Kong M, Bahl A, Kohat D, Wing L, Benamore R
Oxford University Hospitals NHS Foundation Trust, United Kingdom.
Oxford University Hospitals NHS Foundation Trust, United Kingdom.
Clin Radiol. 2024 Dec;79(12):956-961. doi: 10.1016/j.crad.2024.08.025. Epub 2024 Aug 28.
Anterior mediastinal lesions can be a source of uncertainty on imaging, and thymic cysts present a unique diagnostic challenge. Differentiation of non-simple fluid-containing benign simple thymic cysts from small thymic neoplasms is challenging with computed tomography (CT) alone. Additionally, the malignant potential of simple thymic cysts is unclear and guidelines for imaging surveillance are not established.
All imaging studies containing the phrase "thymic cyst" were identified at our institution between October 2012 and October 2022. Studies were excluded if the main radiological diagnosis was anything other than a thymic cyst. This yielded 107 individual patient records, of which 11 did not meet inclusion criteria, leaving 96 unique patients.
While most cysts evaluated remained stable throughout the period of surveillance (53%; n=51), some increased in size (13%), some decreased in size (6%), and some fluctuated (5%). Some cysts changed in internal attenuation/signal characteristics in keeping with interval haemorrhage (6%). 34% of cysts (n=31) demonstrate internal average attenuation values of more than 20HU. Of the entire cohort of patients studied over 10 years, none developed malignancy within the period of surveillance.
Unilocular thymic cysts are most often discovered incidentally but their imaging characteristics can be difficult to interpret on CT, as they are commonly hyperdense and may change in size and internal content. Once simple thymic cysts are adequately characterised with magnetic resonance imaging (MRI) then extended radiological surveillance may not be required.
前纵隔病变在影像学上可能存在不确定性，胸腺囊肿带来了独特的诊断挑战。仅通过计算机断层扫描（CT）将含非单纯液性的良性单纯胸腺囊肿与小的胸腺肿瘤区分开来具有挑战性。此外，单纯胸腺囊肿的恶性潜能尚不清楚，且未确立影像学监测的指导原则。
在我们机构中识别出2012年10月至2022年10月期间所有包含“胸腺囊肿”一词的影像学研究。如果主要放射学诊断不是胸腺囊肿，则排除相关研究。这产生了107份个体患者记录，其中11份不符合纳入标准，剩下96例独特患者。
在整个监测期间，大多数评估的囊肿保持稳定（53%；n = 51），一些囊肿大小增加（13%），一些囊肿大小减小（6%），还有一些囊肿大小波动（5%）。一些囊肿的内部衰减/信号特征发生变化，符合间歇性出血（6%）。34%的囊肿（n = 31）显示内部平均衰减值超过20HU。在超过10年的整个研究患者队列中，在监测期间无一例发生恶变。
单房性胸腺囊肿最常偶然发现，但其影像学特征在CT上可能难以解读，因为它们通常密度较高，且大小和内部成分可能发生变化。一旦通过磁共振成像（MRI）充分明确了单纯胸腺囊肿的特征，可能就不需要进行长期的影像学监测。
