(redirected from blastemal)
Also found in: Dictionary, Thesaurus, Medical.


A mass of undifferentiated protoplasm capable of growth and differentiation.



in the study of regeneration, the accumulation of homogeneous, nonspecialized cells on the surface of a wound after amputation of an organ. Tissues of the organ that is being restored are formed from blastemas in the course of regeneration.

In embryology: (1) a group of cells from which a new individual develops by asexual reproduction in some multicellular animals (Coelenterata, worms, Ascidia, and others); (2) the surface layer of cytoplasm in the cen-trolecithal ova of many arthropods. By means of fine outgrowths the blastema is connected to the cytoplasm, which surrounds the nucleus situated in the center of the ovum.

References in periodicals archive ?
Mpsl defines a proximal blastemal proliferative compartment essential for zebrafish fin regeneration.
Blastomas can be biphasic with epithelial and sarcomatous elements; however, carcinosarcomas do not show a primitive blastemal component.
Blastemal WT], Wilms' tumor can include heterologous elements in addition to these components and Variend et al, [8] in 1984, coined the term teratoid Wilms' tumor for them.
Classification of Hepatoblastoma Major categories Epithelial Fetal, well differentiated (mitotically inactive with minimal mitotic rate of [less than or equal to]2 mitoses per 10, x40 objective fields) Fetal, mitotically active (>2 mitoses per 10, x40 objective fields) Embryonal Macrotrabecular Small cell, undifferentiated Rhabdoid Mixed stroma having osteoid features; rarely striated muscle, cartilage, or minor components as follows: Cholangioblastic (ductal) Intestinal glandular epithelium (teratoid) Neuroid-melanocytic (teratoid) Rhabdomyoblastic Chondroid Blastemal
Skeletal muscle and blastemal elements were also absent.
Multiple histologic sections of the tumor (in excess of 1 per centimeter of tumor) showed the presence of necrotic tissue admixed with epithelial structures and focal aggregates of undifferentiated blastemal tissue (Figure 2).
In young children, the most important differential diagnosis is with Wilms tumor (nephroblastoma), and any cystic tumor encountered in children should be extensively sampled for the presence of blastemal elements, which strongly suggests the diagnosis of Wilms tumor.