To assess the presence of lymphatic vessels in choroid in the human eyes with posterior choroidal melanoma.

Twenty seven cases with posterior choroidal melanoma without ciliary body involvement were selected from the University of Toronto Ophthalmic Pathology Collection and 10 age-matched control eyes without uveal melanoma from Eye Biobank for Research. Paraffin embedded tissue sections of eyes with choroidal melanoma along with control eyes were stained with immunofluorescence method for podoplanin (D2-40), a lymphatic endothelial marker and for collagen IV, a marker for basement membrane. Confocal microscope was used for image acquisition.

In melanoma cases, D2-40-positive lymphatic channels with elongated and dilated lumen were found in peritumoral choroid in 22 out of 27 cases(81.4%)in compare to 3 out of 10 normal eyes. Intratumoral D2-40-positive lymphatics were detected in two cases.

Choroidal lymphatics were detected in eyes with choroidal melanoma. Increased frequency of detection of choroidal lymphatics in eyes with melanoma compared to control eyes suggests the presence of lymphangiogenesis in melanoma cases. Further studies are needed to determine whether changes in choroidal lymphatics have any role in metastasis or local spread of tumor.