This week's artwork was donated by Kate, a pediatric cancer patient who received treatment at The Children's Hospital of Philadelphia .
Most uveal melanomas occur in the choroid.
The ciliary body is less commonly the site of origin and the iris the least common. Melanomas of the iris, which are often of the spindle A variety, are relatively slow growing and relatively benign. The major routes of spread are local extension and by the blood stream. The uveal tract is a vascular structure without lymphatic channels. Systemic metastases are generally hematogenous in origin, and the liver is the most common site.