Lisch nodules (LNs) are the melanocytic hamartomas found in 90% to 100% of adults with NF1 and are the most consistent features of NF1.
Lisch nodules are 1 to 2 mm yellowish-brown dome-shaped solid lesions over the iris surface. They are usually multiple, bilateral, and found in all zones of the iris surface. The color of LNs varies according to the pigmentation of iris or the race. LNs appear darker than blue irides but paler than brown irides. The size and number of LNs tend to increase with age. They are usually asymptomatic, do not cause any visual disturbances, and hence do not require any treatment.
Brushfield spots are characteristic of Down syndrome, and appear as small white grayish spots on the iris periphery.
Brushfield spots are white or yellow colored spots seen on anterior surface of the irides. They are present in 85% of blue or hazel eyed patients with trisomy 21. They can be arranged concentric to the pupils, mid periphery or along the collarette. Only 17% of the brown iris with Down’s Syndrome have Brushfield spots as they are obscured by the anterior concentration of the pigment cells.
The Brushfield spots need to be also differentiated from stromal condensations named “Kunkmann Wolffian” bodies, which are seen in 15% of normal, light colored iris. These are less distinct, less numerous and more peripheral than Brushfield spots with no associated facial dysmorphism.
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