Uveal Melanoma: The Basics

The uvea of the eye is a vascular tunic comprised of the iris, ciliary body, and choroid. Located between the sclera and the retina, the uvea contains dendritic pigmented melanocytes which have the potential to give rise to malignant melanoma. Patients with choroidal melanoma typically present as adults with painless monocular vision loss, while a cataract or glaucoma may be the presenting feature of an anterior segment melanoma.Approximately half of patients with choroidal and ciliochoroidal melanomas eventually die from their tumors. Prognosis is better in cases localized to the iris, presumably because they are recognized earlier.Uveal melanom on right, melanin pigment in middle, and atropic retina on leftMost uveal melanomas produce at least some melanin pigment. For amelanotic cases, confirmatory immunohistochemical stains for melanoma, such as SOX10 and HMB45, may be helpful. Many uveal melanomas perforate Bruch membrane, enter the subretinal space, and invade the retina (see image), resulting in cystic atrophy of the overlying retina.Although a small percentage of melanomas diffusely infiltrate the uvea, the vast majority are well-circumscribed. The presence of distinct margins allows for accurate assessment of tumor size. Measurement of largest tumor diameter (LTD) at the base has prognostic significance. Histologic assessment of uveal melanoma requires subtyping based on the predominance of particular morphologic cell types: spindle type A, spindle type B, and e...
Source: neuropathology blog - Category: Radiology Tags: eye Source Type: blogs