Figure 3

Hyperplasia. A Focal adenomatous hyperplasia in a mouse exposed to i.p corn oil and inhaled MWCNT. A. At low magnification, a focus of bronchoalveolar hyperplasia forms a discrete, hypercellular focus that retains normal alveolar architecture (bar = 200 microns). B. At higher magnification, the hypercellularity is attributable to a population of hypertrophied epithelial cells characterized by moderate anisokaryosis and mild karyomegaly. To distinguish these foci from foci of reactive hyperplasia and because of morphologic similarities to atypical adenomatous hyperplasia in the human lung, we have used the term focal adenomatous hyperplasia for these foci. MWCNT were sometimes seen within or near these foci (bar = 50 microns).