The story
Mildly confusingly, named for mushroom-shaped instances, not for fungal pathogens as the term seems to suggest etymonically; for more, see Wikipedia at mycotic aneurysm § History.
Etymology from Wiktionary, CC BY-SA 4.0.
mycotic aneurysm
Today it means: An aneurysm in which an infectious agent, usually bacteria, grows through the wall of a blood vessel. It leads to an irreversible dilatation of an artery due to destruction of the vessel wall by infection. Full definition →