Wiktionary
n. The spontaneous detachment from the body and elimination of an appendage or an abnormal growth, such as of a polyp.
Wikipedia
Autoamputation is the spontaneous detachment ( amputation) of an appendage from the body. This is not to be confused with self-amputation. It is usually due to destruction of the blood vessels feeding an extremity such as the finger tips. Once the vessels are destroyed, the tissue dies, which is often followed by gangrene. Autoamputation is a feature of ainhum, cryoglobulinemia and thromboangiitis obliterans.
Usage examples of "autoamputation".
Marshall McLuhan describes techno-hysteria as a defensive reaction to change, "a desperate and suicidal autoamputation, as if the central nervous system could no longer depend on the physical organs to be protective buffers against the slings and arrows of outrageous mechanism.