Figure 3.

Pleuropulmonary blastoma type I presented with spontaneous pneumothorax in a 14-month-old girl. A cystic lesion was detected in the right lung. A. This low magnification demonstrates the typical multicystic pattern. Note that the cyst is covered with pleura along one edge (x40). B. The septal stroma is occupied by a uniform population of small primitive cells (x400). C. The septa demonstrates a cambium layer of small primitive cells and a fibrous stroma. Some septa only had the fibrous stroma (x400). D. Desmin immunostain shows the presence of individual positive cells in the septa. A similar pattern of immunostaining was obtained with myogenin (x400).