Figure 4.

Classification. (A) Illustration of the 4 types of lung cancers associated with cystic airspaces according to the classification system of Mascalchi et al. (21). Type I is an exophytic nodule abutting the cystic airspace. In Type II, the nodule shows an endophytic growth in the cyst wall. In Type III there is (partial) thickening of the cystic airspace and in Type IV the lesion has numerous small cystic airspaces, interspersed with ground glass or consolidation; (B) illustration showing the adapted classification system according to Fintelmann et al. (19) defining 3 characteristics (airspace, consistency and loculation) for each tumor.