vegetation (pathology) vegetation (pathology) in medicine, a vegetation is an abnormal growth named for its similarity to natural vegetation. vegetations are often associated with endocarditis. they can be made of fibrin and platelets. histopathology of a vegetation of bacterial endocarditis, taken from a valve repair, h&e stain. types certain conditions are associated with specific vegetation patterns: condition size infective? infective endocarditis related to staphylococcus aureus generally large yes rheumatic fever related to streptococcus pyogenes typically small libman–sacks endocarditis related to systemic lupus erythematosus small no (sterile) nonbacterial thrombotic endocarditis (nbte) small no (sterile)