Figure 2.

This biphasic medulloblastoma contains nodules (A–C) with the same phenotype as nodules in a nodular/desmoplastic medulloblastoma, but they lack perinodular and internodular desmoplasia (D, reticulin preparation). Intranodular tumor cells express NEU‐N and P27 (E, P27 antibody), and have a much lower Ki‐67 immunolabeling index than surrounding internodular regions (F, MIB‐1 antibody). An anaplastic phenotype characterized the internodular regions of some biphasic medulloblastomas (G). A pattern of “enlarged” rosettes was evident in a few biphasic tumors (H).