Intraspinal bronchogenic cyst: ultrastructural study of the lining epithelium.

This report describes the ultrastructural characters of the lining epithelium of a symptomatic intraspinal bronchogenic cyst at the C5-T2 level of a 21-year-old female. Six distinct cell types were recognized: ciliated cells, non-ciliated cells, and goblet cells that reached the lumen, and basal cells, Kulchitsky cells and undifferentiated cells that were basally located and did not reach the lumen. The microvilli of non-ciliated cells were coated with granulofibrillary material. Discharge of granular contents from goblet cells was noted. Abnormal cilia, particularly compound cilia, were frequent. Complex interdigitations of cytoplasmic membrane with prominent desmosomes were present in the pseudostratified region. Kulchitsky cells contained characteristic membrane-bound dense-core neurosecretory granules. Intraepithelial unmyelinated axons were observed but none were closely associated with Kulchitsky cells. The types of cells forming the lining epithelium of the present cyst and their topographic distribution within the epithelium are very similar to those of the normal tracheobronchial epithelium.