Pineoblastomas have the typical appearance of small round blue cell tumor with striking resemblance to medulloblastoma and neuroblastoma. They are composed of densely packed sheets of anaplastic cells with large hyperchromatic nuclei and minimal cytoplasm. Necrosis and brisk mitotic activity are also usually present. The tumor is poorly demarcated and often infiltrates into the surrounding parenchyma. Courtesy of: Dr. Luciano de Souza Queiroz, Dept. of Pathology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, São Paulo State, BRAZIL. Additional images are here.