Purpose: Invasion of tumor cells into blood vessels is essential for metastasis of uveal melanoma. The occurrence of ingrowth of tumor cells in blood vessels in uveal melanoma was analyzed, and this parameter was compared with the survival of the patients.
Methods: Between 1972 and 2007, 643 eyes primarily enucleated for uveal melanoma were evaluated histopathologically. Survival data were obtained from charts and from the Integral Cancer Center patient registry.
Results: No vascular ingrowth of tumor cells occurred in 59% of the eyes, whereas 18% had tumor cell ingrowth in vessels inside the tumor, 10% in vessels outside the tumor, and 8% in vessels inside as well as outside the tumor. The presence of any intravascular ingrowth of tumor cells correlated significantly with the diameter (P < 0.01) and prominence of the tumor (P < 0.01), as well as with non-spindle-cell type (P = 0.03) and intrascleral ingrowth (P < 0.01), and was associated with a worse survival. When extravascular matrix patterns were not included in the multivariate analysis, intravascular ingrowth came out as an independent prognostic factor, but this was not the case when extravascular matrix patterns were included in the multivariate model.
Conclusions: Intravascular ingrowth of tumor cells in uveal melanoma occurs frequently in combination with well-known histopathologic factors such as large tumor size, epithelioid cell type, and intrascleral ingrowth.