Lambl's excrescences are usually described as filiform
(threadlike) fronds. They were first described by Vilem Dusan
Lambl, a Bohemian physician.
They occur, by definition, along
valve closure lines, where minor endothelial damage promotes
thrombus formation and deposition of layers of mucopolysaccharide
matrix. They occur most commonly attached to aortic valve cusps.
Most patients are asymptomatic. However, excrescences can embolise
in which case the consequence may be an embolic stroke. In such
cases, anticoagulation is usually considered. Patients suffering
multiple embolic strokes are offered surgical debridement of
excrescences (other causes having been excluded). Asymptomatic
patients should be monitored for embolic events.
Papillary fibroelastomas are
microscopically similar though the term tends to be applied to
larger lesions. They are also usually attached to valve cusps or
leaflets but can occur away from valve closure lines and on the
endocardial surfaces of atria and ventricles.