00:00 In this lecture, we will quickly review retinoblastoma in childhood; tumor of the eye. 00:07 Here is the characteristics of retinoblastoma. 00:11 It happens in one in 20,000 live births and thus there's about just over 300 cases every year in the United States and Canada. 00:20 So it's not that common, but it's a unique condition, so we'll discuss it. 00:25 Patients may have unilateral or bilateral retinoblastoma. 00:30 The unilateral disease is typically a spontaneous mutation in the Rb1 gene. 00:37 This is 70% of cases, and it typically presents between the age of two and five. 00:44 On the flipside, we can see bilateral disease. 00:48 This is a result of having inherited a mutation in the Rb1 gene and just getting a second hit. 00:57 This is 30% of cases and this presents in children under of year of age so they present a little bit earlier. 01:05 This is one of the typical, small blue round cell tumors, it's intraocular and it presents typically in infancy in patients who've inherited the disease. 01:16 It's associated with a genetic mutation of Rb1 or the retinoblastoma gene. 01:22 Rb1 is an important oncongenic tumor suppressor gene found on the 13th chromosome at 13q14. 01:33 Basically, a mutation in this gene causes cellular proliferation and cell cycle dysregulation, resulting in a clonal population of cells that can form tumors typically in the eye. 01:48 And it's associated with the development of other tumors as well. 01:51 Retinoblastoma can metastasize to other organs in the body. 01:56 So, this gene is something we think of in our typical two-hit hypothesis. 02:04 Remember, everyone has two copies of the retinoblastoma gene. 02:08 Here's a normal child who freakishly had one mutation in a cell population. 02:15 That population of cells then made a new set of clonal populations and then they have freakishly another mutation. 02:23 This is the more common type where they're not born with a mutation and this happens a little bit later in life because it takes more time to sort of - through absurdly bad luck have two hits on both genes. 02:37 This is to be compared with someone who has inherited this problem. 02:41 They've inherited one copy already not working, in this case, it's on dead sperm. 02:46 And then they only need one hit before they develop the tumor, so this would be more commonly in the 30% of children who have actually inherited the poor portion of the gene. 02:57 So how does it present? Well in infants or later in childhood, it's going to typically present with leukocoria. 03:05 Sometimes patients notice in a photograph that one eye is red and the other one isn't. 03:09 Often, it's picked up on routine screening by doctors. 03:13 So leukocoria is a white reflection in the pupil in infancy. 03:17 It can also be associated with strabismus because these patients may not be seeing very well and a decreased visual acuity. 03:25 They can also develop heterochromia of the iris as you can see here. 03:31 In general, these patients will get a CBC with differential which can be abnormal if there is bone metastasis of the lesion. 03:39 We will also get an LP to assess for spread into the CNS. 03:44 What are the radiologic findings? Well, we usually sedate the patients and do an ophthalmologic evaluation of both eyes under sedation. 03:54 We often will ultrasound the eyes to determine the extent of disease. 03:58 And we'll get a CT +/- an MRI of the orbits and brain to further characterize where this lesion is. 04:06 Lastly, we may get a bone scan if we're worried about boning metastasis as a way of determining if there are any. 04:14 So how do we treat this tumor? Well, we prefer if we can to do vision sparing techniques. 04:21 This will involve graduation, chemotherapy, surgery, photocoagulation, cryotherapy, and thermotherapy. 04:28 They were all a bunch of different ways the ophthalmologist can aggressively attack this disorder. 04:32 Unfortunately, there are times when we do have to do surgical enucleation of the eye and we will remove the affected eye. 04:41 This is usually in unilateral cases. 04:44 We don't do this typically in cases of bilateral disease because the risk is so profound that the other eye will be affected. 04:51 Complications are what you might expect from a germline mutation. 04:57 This is an inherited germline mutation, so in those minority of patients who have inherited, they absolutely have risk for other malignancies for the rest of their life. 05:07 Vision loss is from surgery or from disease and that we can expect. 05:11 Additionally, for those who have a secondary malignancy, there is a radiation risk of osteosarcoma and there can be also risk of skin cancer as well. 05:23 So that's a brief summary of retinoblastoma in childhood, thanks for your time.
The lecture Retinoblastoma in Children by Brian Alverson, MD is from the course Pediatric Oncology. It contains the following chapters:
Which of the following is true regarding bilateral retinoblastoma?
Which of the following is not typically found in patients with retinoblastoma?
Which of the following is true regarding retinoblastomas?
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Excellent lecture as usual. Thank you very much! It makes the topic so much clearer.