 I'll spare you, there will be no singing today. So, today we're going to be talking about the iris. So, as a medical student, the iris is often your favorite structure to look at. Not only is it beautiful, very well-pigmented, but it's often really the only structure that you can find on us at the lab exam. So, unfortunately, there's often not a lot of pathology with the iris, and when there is, it's often pretty benign. However, occasionally, this beautiful structure of the iris can turn deadly if there's not close monitoring. So, we have a case today. So, the 13-year-old boy with a history of congenital sector iris melanocytosis presents with a new pigmented and elevated lesion on his right iris near the iridocornial angle. First notice is the lesion about six months ago and since then, it has not really grown. So, his exam is a visual acuity was 2020 and his intraocular pressure was normal. So, here you can see that this is an external photograph of the eye. Notice the darkly pigmented melanocytosis with peripherally there is this new growth supernasally. So, here is another view of the lesion I've highlighted in black here. Notice this new growth here on this portion of the iris. Here is a close-up view of the iris melanocytosis and the growth proceeding here. Here we see that this is a gonioscopy view looking at the angle of the iris here and I've outlined here the growth concern here is you want to look for seeding. You want to look for any types of seeds in this portion of the angle for that would be highly addictive of a melanoma. Here you look at the growth you notice the intrinsic vascularity of this growth. Zooming in on this you can get a close view of the growth and also be into your chamber notice that there's no seeding on the iris or the anterior chamber and also here you can notice zooming in that you see that there are no prominent feeder vessels growing right into this growth. So, this is an anterior chamber osmanatomy and what we'll be focusing on right here is going to be the iris. So, here is this patient's anterior OCT and I've highlighted the lesion here and it showed that it was a 0.5 millimeter depth lesion by about a 3.5 millimeter in width growth. So, the big question is this an iris nevus, is this an iris melanoma? That's the big question that I want to tackle today. So, the reason is if you look here on the left how do we know the difference between an iris nevus here on the left which in only four years transformed into a melanoma? We're in this one, the nevus on the left here in only two years transformed into a melanoma. So, first some background. Dr. Carol Shieldett, Will's Eye Institute looked at about 4,000 iris lesions over about a 35-year period and categorized as to what their etiology was. They found that about a quarter of these lesions and children ended up being iris nevi and then in middle age and senior adults almost half of the lesions arrived as nevi showing that the most common lesion you're going to find on the iris is going to be an iris nevi. Of note, middle aged in their study was categorized as 41 to 60 just in case you're wondering if you made the cut or not. So, looking at the rates of transition of nevi that are already found on the iris that will transition to melanoma in a study by Torito et al. They found that 5% of melanoma after five years. Additionally, studied by Shields found that after 15 years 8% of these original nevi eventually transitioned into melanoma. So, the iris is part of the uvea structure which if you look at the breakdown of the different malignancies, choroidal melanoma is going to be the most common form of uvea melanoma and iris melanoma is actually going to be the least common. So, if you have an iris melanoma, why is it so important to catch it early? The reason is because with an increase of one millimeter depth of iris melanoma, you have an increased rate of metastasis by five years. So, this is a pictorial illustration of iris melanoma and the rate at which they will metastasize after a certain period of time. So, after five years, Dr. Shields and her colleagues found that 3% of melanoma would eventually metastasize. After 10 years, 5% of these melanoma would metastasize. And after 20 years, 10% of these melanoma would eventually metastasize and become systemic. So, how do we identify iris melanoma? So, if you remember back to medical school, we had this handy-dandy mnemonic of skin melanoma with the ABCD mnemonic. Additionally, Dr. Shields and her colleagues came up with a similar mnemonic but specifically for iris melanoma. This has been known as the ABCDEF, which we will be going through specifically today. So, A is for age, young. So, iris neva that were found in patients age 40 years or less showed a 3% or not 3% or three times more likely to become a melanoma than those that occurred in older individuals. B is for blood. So, a single episode of hypochema was associated with 9 iris nevus becoming melanoma. The clock hour and inferior. Specifically, this is referring to about the sectors of 4 o'clock to 9 o'clock on the distribution of the iris. You can see the distribution here and if the original nevus occurred in this portion of the iris, it was associated with a 9 times greater chance of becoming melanoma. D is for diffuse or involving the entire surface of the iris. Nevi that met this criteria were 14 times more likely to become melanoma. E is for ectropion. So, ectropion UVI is the posterior pigmented portion of the iris that is folding forward through the pupil, often being dragged by the melanoma itself. If you note here on this, if you note the melanoma in the lower inferior portion, it's pulling the posterior portion of the iris forward forming this ectropion UVI. F and lastly is for feathery margin. So, this is referring to the geographic associated with 3 times increased risk of becoming melanoma. So, if you note here, this nevus in the bottom, I've outlined these feathery kind of fanning out borders here. Additional markers which are indicative of a nevus that would be at risk for becoming a melanoma or a melanoma itself are seeding both on the iris itself and in the angle, feeder vessels, nodule formation, and also intrinsic vascularity. So, in conclusion, iris nevi are the most common iris lesion that you are going to see statistically. Additionally, the rate of their transition from benign to malignant is represent after 5 years and about 8% after 15 years. If we look at our patient and going through this ABCDEF criteria, he didn't meet very many of these. Only meeting one for being a young age and also an ancillary criteria of intrinsic vascularity. As such, he was diagnosed with a benign iris nevus with a low potential for transition into melanoma. He was eventually followed over the next couple of years and they noticed minimal growth and no seeding of this nevus. As such, the patient and the family was comfortable that this would be a benign process. So, my hope as we have gone through this today is as we see these lesions, as we see iris nevus in the clinic that by applying this criteria of the ABCDEF, we can be both more confident and more accurate in differentiating between iris nevi and iris melanoma. So, in terms of the angle, that's a really highly risky area for tumor, for growth. I didn't read specific numbers in terms of how much increase risk you are at to have a nevus that's growing near the angle, but that's one of the reasons that you have to do gonioscopy very frequently to see how close that growth has become to the angle. So, that's really an important difference, they reclassified it. Yeah, exactly and I looked into it. Nobody has an explanation for that. This is one of those statistical things. Yeah, it's possible.