carolyn
blast = referring to immature (developmentally speaking) or primative cells.
You're not too far off the mark. A neoplasm is a new growth, and can refer to both a newly fertilized egg, or a tumor. So, your logic is very good :-)
Like "fetal" sounds like a combination of "fecal" and "fatal."
("I didn't kill an unborn baby as long as your index finger, I merely removed 5 cm fetal material...")
See Politics and the English Language by George Orwell.