EWINGS SARCOMA/ PRIMITIVE OR PERIPHERAL NEUROECTODERMAL TUMOR

Ewings sarcoma : Monotonous, homogenous population of tumor cells having hyperchromatic nuclei. Extensive areas of necrosis are seen (top) (H&E,X100)

Ewings sarcoma : Tumor cells having small round uniform cells with hyperchromatic nuclei and scant cytoplasm. Tumor cells are arranged in organoid pattern (H&E,X400)

Ewings sarcoma : Tumor cells having small round uniform cells with hyperchromatic nuclei and scant cytoplasm. some of the tumor cellsshow nuclear indentations. Tumor cells are arranged in organoid pattern (H&E,X400)

Ewings sarcoma : Sheets of small round uniform cells with scant cytoplasm and hyperchromatic nuclei. The cells are divided into irregular lobules by fibrous strands (H&E,100)

PNET: Tumor cells arranged rosette like pattern with neurofibrillary core (H&E,X400)

PNET: Sheets of tumor cells with few foci showing tumor cells arranged around central lumen (Flexner Wintersteiner rosette) (H&E,X400)