Normal EOG values in intraretinal metastasis from cutaneous melanoma: a case report

Purpose: The electro-oculogram (EOG) is a powerful test to diagnose primary and metastatic choroidal tumors. While in benign tumors light-peak to dark -trough ratio values are in the range of normal subjects, these values appe ar highly altered in eyes affected by malignant choroidal tumors. Here we r eport a clinical case of a patient with intraretinal metastasis from cutane ous melanoma; notwithstanding the malignancy of the tumor, the EOG doesn't present alterations. Methods and results: Standard electro-oculographic rec ordings were performed before and after local excision of the tumor; record ings from the normal eye were taken as control. The EOG values were always normal in both eyes. Histological sections showed no evident change in the cell population of the retinal pigment epithelium (RPE) and Bruch's membran e. Conclusion: Our results suggest that the presence of an intact RPE is a crucial requirement to obtain a normal EOG.