Congenital cystic diseases of the lung include lobar overinflation (LOI), cystic adenomatoid malformation (CAM), pulmonary lobar sequestration (PLS), and congenital bronchogenic cyst (CBC). Their pathologic changes vary and pathogeneses are
complicated.
In order to make the correlation between the pathologic changes of the congenital cystic lung diseases and bronchopul-monary foregut development the author reviewed development of the bronchopulmonary bud in the early period of embryogenesis.
Also
reviewed were pathologic materials (gross and microscopic slides) and clinical histories of LOI(one case), CAM(three), PLS(six) and CBC(four cases).
The followings were characteristics of clinical and pathologic manifestations of the congenital cystic disease of the lung
LOI was manifested in the neonatal or infantile period with dyspnea and funnel chest. Overdistention of the alveoli and bronchioles was pathologic characteristics. Faulty formation of cartilage in the bronchial wall was the fundamental defect led
to the
overdistention of alveoli.
CAM was presented in the infancy with cough and dyspnea and involved an entire lobe of the lung. Three distinct types of CAM according to the size of cysts were classified. In type I. large cyst type, a single or a few huge cysts replaced the
entire
lobe of the lung parenchyma. The cyst walls were made up of the tissue similar to immature bronchial structrues. Type II consisted of many large and small cysts which were lined by simple bronchiolar epithelium.
Type III, solid type, was made up of tiny cystic spaces reminiscent of immature alveolar structures.
Of six cases with PLS intralobar (ILS. Five cases) and extralobar pulmonary sequestration(ELS, one cases) were distinguished. ELS appeared in the neonatal period with dyspnea and ILS was presented in the wide range of ages with revealed large and
small
cysts similar to those of CAM, type II.
CBC appeared through many decades of ages. Intrapulmonary cyst was manifested as cough with sputum, and extrapulmonary (mediastinal or neck ) cysts appeared as a mass. The cyst wall had the structure similar to bronchial wall of the fetal stage.
These four congenital cystic lesions of the lung share similar clinical and embryologic characteristics. The pathologic features of the lesions are thought to be the manifestation of bronchopulmonary developmental anomalies in various stages
embryogenesis.
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