As nouns the difference between malformation and polysomia
is that malformation is an abnormal formation while polysomia is a fetal malformation in which multiple bodies are partially fused together.
malformation
English
Noun
(
en noun)
An abnormal formation.
(teratology) An abnormal developmental feature of offspring.
See also
* (l)
polysomia
English
Noun
(-)
A fetal malformation in which multiple bodies are partially fused together