Figure-2.

Type II PPB are characterized by the presence of both cystic and solid areas. Underneath the epithelium of the cystic structures a condensation of the immature cells can be noted in some cases forming a cambium-like layer (a). The solid components can have a wide range of morphology from a fibrosarcoma-like appearance (a) to a predominance of a rhabdomyoblasts proliferation (b). In some cases, the solid areas are composed of primitive small immature cells (c). The solid areas might also show frank anaplasia (d). All photomicrographs represent different cases.