What are tumors of blastema?

Made up of immature cells similar to those derived from the embryonic development (blastema) of a full tissue organ, appear most often in childhood, often very fast growing, prognosis depends on age and stage, Sometimes able to mature under the effects of chemotherapy. The most frequent are : Nephroblastoma, Neuroblastoma Histologically, these tumors mimic the appearance of a blastema, and combine: Undifferentiated blastematous areas, made of sheets of "small round and blue cells“ With Differentiated blastematous areas: differentiation varies according to the type of blastema: epithelial (primary renal tubes in a nephroblastoma), neuronal (in a neuroblastoma) or mesenchymal (muscle differentiation in certain nephroblastomas or medulloblastomas)