Retinal pigment epithelial tumors are both congenital, and acquired. The most common are created by laser,, cryotherapy, infection, inflammation, trauma, neovascularization,, and long-standing SRF. However, there exist, other forms, such as congenital hypertrophy of the RPE, (CHRPE), acquired hamartomas, as well as adenomas, and adenocarcinoma (Mind map 31-1). It is important, for the eye cancer specialist to be familiar with retinal, pigment epithelial tumors, as they need to be differentiated, from choroidal melanoma.1, CHRPE, or “bear tracks”, are typically discovered in children, and young adults as multifocal, flat, inactive, and, grouped pigmented fundus lesions. They are associated, with familial adenomatous polyposis (FAP), suggesting, their treatment must be coordinated with a gastroenterologist, (see Chapter 10).2,3 Hamartomas of the RPE can, be subdivided into simple acquired hypertrophic or idiopathic, RPE hamartomas, to more complex combined, hamartomas of the retina and RPE, and unilateral RPE, dysgenesis.4,5, Retinal pigment epithelial dysplasias include idiopathic, RPE hyperplasia, adenoma, and adenocarcinoma, and, are described later in this chapter. These 3 entities are, clinically and histopathologically challenging to distinguish, and likely represent stages along a continuous, spectrum (Mind map 31-1).6
Chapter Keyword: choroid
Metastatic Cancer to the Eye, Lids, and Orbit
Though innumerable scientific articles start with “the most common intraocular malignancy is choroidal melanoma,” choroidal metastases are much more common.1 Uveal metastases are seen histologically at postmortem in up to 12.6% of patients dying from metastatic cancer.2 However, clinically observable metastatic disease has been noted in only 2%–7% of patients with dissem-inated disease.3-5 Similarly, orbital metastases have been found in up to 5% of patients with systemic malignancy.6,7 This disparity is likely due to the patients being asymptomatic, having little time to live, or a combination of both.5,8 Further, systemic treatment may render the ocular metastasis occult, leaving the patient and oncologist unaware of its existence. , However, the life expectancy for patients with metastatic disease from cancers that commonly spread to the eye has improved over time, particularly in the case of breast cancer.9,10 This longevity has resulted in increased numbers of patients needing ocular treatment to prevent vision loss and ensure their quality of life.11,12 Further, ocular metastases may be the first presentation of systemic disease. One study found that uveal metastases from lung carcinoma (47%), pancreatic cancer (37%), and lung carcinoid (33%) often preceded the systemic diagnosis; by contrast, 94% of patients with breast metastases had a history of the disease.13 Other studies have reported similar results.9,14,15 Similarly, 15% of patients with orbital metastases do not have a cancer diagnosis at presentation.7 Some ocular metastases may, albeit rarely, occur after a tumor has been in remission for years (reported up to 43 years later), which may be a diagnostic shock.16-18 The ocular presentation of metastatic disease is also changing. For instance, because the eye is a relatively immunologically privileged site, vitreous metastases of cutaneous melanoma (Fig. 35-1) are increasingly common in patients on checkpoint inhibitors and who are otherwise in remission.19,20 Prior to this therapy, vitreous involvement was seen only in 18% of eye, lid, or orbital cutaneous melanoma metastases.21 , Further, there has been an evolution of local therapies. The goal of local treatment is to retain vision. Thus, observation for response to systemic therapy may work but risks vision loss in cases where the reattachment of the macula is delayed. Treatments to decrease exudative retinal detachments include laser (e.g., PDT), intravitreal anti-VEGF injections, and steroid implants.22 Larger tumors may be treated with EBRT and smaller extramacular tumors with plaque brachytherapy. However, both forms of radiation carry dose-dependent risks of long-term side effects in longer-lived patients.23 Finger has used anti-VEGF drugs as a bridge therapy to more definitive EBRT irradiation.
Functional Ophthalmic Oncology Anatomy
Anatomic and tumor-specific factors play dominant roles in clinical decision-making. Select examples include eye¬lid tumor position directing the postresection method of repair (see Chapter 37), orbital optic nerve sheath obstruction requiring slotted plaques (see Chapter 18) to completely cover juxtapapillary intraocular tum¬ors, and the shape of the orbit affecting the orbitotomy approach. In consideration of the basic anatomy of the eyeball, the adnexa, and the orbit, this chapter high¬lights select salient anatomical features that affect tumor growth, metastasis (regional or distant), diagnosis, and management.