Lisch nodule, also known as iris hamartoma, is a pigmented hamartomatous nodular aggregate of dendritic melanocytes affecting the iris.
These nodules are found in neurofibromatosis type 1, and are present in greater than 94% of patients over the age of six.
Lisch nodule are clear, yellow-brown, oval to round, dome-shaped papules that project from the surface of the iris.
These nodules typically do not affect vision, but are very useful in diagnosis.
They are detected by slit lamp examination.
Immunohistochemistry stains positive against the proteins vimentin and S-100, and points to an ectodermal origin for the nodules.
They are rarely be seen in neurofibromatosis type 2.