lymphoblastListen to pronunciation(LIM-foh-BLAST)A lymphocyte that has gotten larger after being stimulated by an antigen. Lymphoblast also refers to an immature cell that can develop into a mature lymphocyte.Enlarge this image in new windowBlood cell development. A blood stem cell goes through several steps to become a red blood cell, platelet, or white blood cell. Search NCI's Dictionary of Cancer TermsStarts withContainsBrowse:ABCDEFGHIJKLMNOPQRSTUVWXYZ#