Mino M, Noma S, Kobashi Y, Iwata T
Department of Respiratory Medicine, Tenri Hospital, Nara, Japan.
Clin Radiol. 1995 Jun;50(6):357-63. doi: 10.1016/s0009-9260(05)83131-9.
In patients with cryptogenic fibrosing alveolitis (CFA), subpleural large cysts are sometimes seen within honeycombing on computed tomography (CT). These cysts may be interpreted as bullae and the coexistence of emphysema with CFA might be assumed. We evaluated whether cystic spaces in honeycombing become larger in patients with CFA on serial CT scans. CT scans were obtained in 16 patients with CFA, who had undergone two CT examinations (6 to 43 months, mean 25.1 months apart), were reviewed focusing on the changes in size of the cystic spaces in honeycombing. The mechanism of enlargement of cystic spaces was investigated using microscopic serial sections of autopsied specimens. In 15 of 16 patients, the cystic spaces in honeycombing were larger on the second examination. Histologically, stenosis of bronchioles and slit-like structures between cysts and bronchioles were detected in addition to alveolar septal dissolution and bronchiolectasis. Both the bronchiolar stenosis and the slit-like gaps have the potential to work as check-valves and increase the volume of cystic spaces. Therefore, in the evaluation of CFA, large cysts should be interpreted with caution to avoid misinterpretation of the cysts as bullae associated with emphysema. From the results of this correlative study, we suggest that a check-valve effect is an important mechanism in the formation of large cysts in honeycomb lung.
在隐源性纤维性肺泡炎（CFA）患者中，计算机断层扫描（CT）显示蜂窝状结构内有时可见胸膜下大囊肿。这些囊肿可能被解释为肺大疱，进而推测CFA与肺气肿并存。我们评估了CFA患者在系列CT扫描中蜂窝状结构内的囊性间隙是否会变大。对16例接受过两次CT检查（间隔6至43个月，平均间隔25.1个月）的CFA患者的CT扫描进行回顾，重点关注蜂窝状结构内囊性间隙大小的变化。使用尸检标本的显微镜连续切片研究囊性间隙扩大的机制。16例患者中有15例在第二次检查时蜂窝状结构内的囊性间隙更大。组织学上，除了肺泡间隔溶解和细支气管扩张外，还检测到细支气管狭窄以及囊肿与细支气管之间的裂隙样结构。细支气管狭窄和裂隙样间隙都有可能起到单向阀的作用，增加囊性间隙的容积。因此，在评估CFA时，对大囊肿的解读应谨慎，以免将囊肿误判为与肺气肿相关的肺大疱。根据这项相关性研究的结果，我们认为单向阀效应是蜂窝肺中形成大囊肿的重要机制。
