1) Degeneration 2) Retrogression 
Cataplasis ... A degenerative change in cells or tissues that is the reverse of the constructive or developmental change; a return to an earlier or embryonic stage. ... Synonym: retrograde metamorphosis, retrogression, retromorphosis. ... Origin: cata-+ G. Plasis, a molding ... (05 Mar 2000) ... 
Type: Term Pronunciation: kat′ă-plā′sē-ă, -plā′sis Definitions: 1. A degenerative change in cells or tissues that is the reverse of the constructive or developmental change; a return to an earlier or embryonic stage. Synonyms: retrograde metamorphosis1, retrogression, retromorphosis
[n] - (biology) degenerative reversion of cells or tissue to a less differentiated or more primitive form
noun (biology) degenerative reversion of cells or tissue to a less differentiated or more primitive form