UVEAL MELANOMA - COMPARISON OF THE PROGNOSTIC VALUE OF FIBROVASCULAR LOOPS, MEAN OF THE 10 LARGEST NUCLEOLI, CELL-TYPE, AND TUMOR SIZE

Purpose: This study was performed to determine the prognostic signific ance of the presence of loops defined as periodic acid-Schiff-positive fibrovascular septa that completely surround lobules of tumor cells i n cases of uveal melanoma. Methods: The presence of loops was evaluate d using an ordinary light microscope and routinely stained periodic ac id-Schiff and hematoxylin sections from 496 posterior uveal melanomas without knowledge of the follow-up data on the patient. Results: At 15 years, survival decreased from 67.5% to 33.8% when complete loops wer e present. Univariate Cox regression analysis indicated that the prese nce of loops was an indicator of poor outcome, and was better than age but not as good as the mean diameter of the largest nucleoli, cell ty pe, or tumor size.Conclusions: The presence of loops, as evaluated in this study, was not as strong an indicator of poor outcome as were loo ps assessed in a previous study of 234 cases from another laboratory. The authors suspect this difference may be due to their only using rou tinely stained sections without a green filter, as was used in previou sly reported studies. The authors' description of [oops does not requi re any special equipment and gives sufficiently useful results to just ify its inclusion by the pathologist in reports of such specimens. A d escription of vascular loops should be added to the use of the modifie d Callender cell type, tumor dimensions, mitotic count, extraocular ex tension, and lymphocytic infiltration in the final pathologic report.