Comparison of direct and microslide pathology measurements of uveal melanomas

Many investigators have shown that large cilio-choroidal melanomas are more likely to be associated with an unfavorable outcome than small tumors by using data retrieved and measured from pathology files. In the past, the measurement of largest tumor dimension (LTD) may not have been recorded at the time of the gross examination, because the significance of this observation was not appreciated. If this information is not available, authors can eliminate cases from their studies, take all their measurements directly from glass microslides, or combine clinical estimates of tumor size for some cases with gross measurements for others. To date, there has been no formal study to compare the measurement of tumor dimensions from glass microslides with measurements made at the time of gross examination by the pathologist. This study of 112 cilio-choroidal melanomas reveals that measurements of the LTD made from the glass microslide correlate with direct measurements taken from the cut surface of the globe at the time of sectioning. Additionally, measurements of the LTD from the glass microslide are at least as effective in predicting patient outcome as direct measurements. These findings suggest that measurements of the LTD from the glass microslide provide as much prognostic information as direct measurements if it is known that the eye was cut to obtain representative sections of the tumor.