Ultrastructural appearance of iris flocculi associated with a thoracic aortic aneurysm and dissections

Pigmented iris cysts are characterised by cystic neoplasia originating from the pigmented epithelium of the iris and, similar to pigmented tumours of the iris, require differential diagnosis.1 Shields1 reported multiple pigmented epithelial cysts at the pupillary margin as iris flocculi in association with a thoracic aortic aneurysm and dissections (TAAD).2 Recently, a mutation in smooth muscle α-actin (ACTA2) was identified as a risk haplotype.3 We report two cases of bilateral pigmented iris flocculi caused by a mutation in ACTA2. A 32-year-old woman with visual disturbances in brightly illuminated surroundings was referred to our clinic. There was no history of birth or postnatal ocular trauma or surgery. She had been diagnosed as having TAAD at age 30. A mutation (Arg149Cys) in smooth muscle ACTA2 was identified (fig 1A). Slit-lamp examination showed that the cysts were bilateral, oval and pigmented, and lined the pupillary …