Uveal Melanoma: A Prototype for the Study of Hematogenous (Blood Borne) Dissemination of Cancer
There are no lymphatic channels within the eye. Therefore, with only very rare exceptions, uveal melanomas disseminate exclusively through the blood stream. Cutaneous (skin) melanomas typically disseminate first to reginoal lymph nodes.
Suggested Reference: Clarijs R, et al. Lack of lymphangiogenesis despite coexpression of VEGF-C and its receptor Flt-4 in uveal melanoma. Invest Ophthalmol Vis Sci 2001;42:1422-1428.
Retinoblastoma, the most common primary intraocular tumor of children, also typically disseminates hematogenously. Retinoblastoma is a highly angiogenic tumor. Nevertheless, children with retinoblastoma tend to survive their primary cancers unless there is evidence of invasion by the tumor into the optic nerve, into the uvea, or outside the eye.
Thus, in retinoblastoma, the presence of florid angiogenesis does not equate to malignant behavior. The relationship of angiogenesis to aggressive behavior in uveal melanoma is the subject of considerable investigation in our laboratories.