The ultrastructure of pulmonary hamartoma.

Ultrastructural and histochemical examination of chondromatous pulmonary hamartomas revealed the epithelial component to be comprised elements similar to those lining the distal bronchioles and the alveoli of adult lung. The stromal cells nearest the epithelium include a population resembling mature fibroblasts and a population of glycogen-containing, primitive appearing cells. More deeply situated stromal cells showed features of chrondroid differentiation.