spongioblastoma /spun′jē·ōblastō″mə/ pl. spongioblastomas, spongioblastomata [Gk, spongia + blastos, germ, oma, tumor] , a neoplasm composed of spongioblasts, embryonic epithelial cells that develop around the neural tube and transform into cells of the supporting connective tissue of nerve cells or cells of lining membranes of the ventricles and the spinal cord canal. Also called glioblastoma, gliosarcoma, spongiocytoma.