Pleuropulmonary blastoma (PPB) is a rare and aggressive pediatric malignant tumor that occurs in the pleural cavity or the pulmonary parenchyma. The tumor cells are thought to stem from subepithelial embryonic mesenchymal cells capable of differentiating into both mesenchymal and epithelial cells. These multipotent cells can give rise to different tissue components, including smooth muscle, cartilage, and fibroblasts. Morphologically, PPB is categorized into three subtypes: type I is purely cystic, type II is a mixture of cystic and solid, and type III is purely solid. Treatment is typically surgical for type I PPB and a combination of surgery, radiotherapy, and chemotherapy for types II and III. This chapter summarizes our current understanding of the pathology, clinical and radiologic presentation, diagnosis, treatment, and prognosis of PPB.