This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Homer wright rossette are seen in-a)  Neuroblastomab)  Astrocytomac)  Meningiomad)  Pinealoma \nSelect and explain. \nA. ad, B. c, C. ac, D. ab', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Rosettes\n\nRosettes are pathological findings characterized by a halo or spoke wheel arrangement of cells surrounding a central\xa0core or hub.\n\nType of Rosette\n1. Flexner - Wintersteiner Rosettes\n\nA halo of cells surrounds a largely empty central hub but small cytoplasmic extension from cells project into the lumen.\nIt is characteristic of retinoblastoma.\nMay also be seen in → Medulloblastoma, Primitive neuroectodermal tumor, Pineoblastoma.\n\n2. Homer Wright rosettes\n\nA halo of cells surrounds a central hub that contains a meshwork of fibres (neutrophil rich centre).\nHomer-Wright rosettes are characteristic of neuroblastomas and medulloblastomas.\nMay also be seen in →\xa0Primitive neuroectodermal tumors (PNET), Pineoblastomas, Retinoblastomas.\n\n3. True ependymal Rosette\n\nA halo of cells surrounds an empty lumen.\nIt is characteristic of ependymomas.\n\n4. Perivascular pseudorosettes\n\nA halo of cells surrounds a blood vessel.\nThe term pseudo is used because the central structure is not formed from the tumor itself, and represents a nonneoplastic element.\nMay be seen in\n\tEpendymonas\n\tGlioblastomas\n\tMedulloblastomas\n\tRetinoblastoma\n\tPrimitive neuroectodermal tumors\xa0\xa0\xa0\n\tMonimorphous pilimyxoid astrocytoma\n\tCentral neurocytoma', 'role': 'assistant'}]