Tumor Necrosis Is a Prognostic Factor in Thick Cutaneous Melanoma

The significance of tumor necrosis in cutaneous melanoma has not been well elucidated. The purpose of this study was to explore the prognostic impact of necrosis in comparison with other known clinicopathologic factors in these tumors. Initially, 457 consecutive cases of nodular cutaneous melanoma (1981 to 2008) were included in this series. Tumor necrosis was assessed on hematoxylin and eosin-stained sections and was recorded as significant when an area of at least a quarter of a high-power field (x400; 0.07 mm(2)) was occupied by necrotic cells and as sparse when clusters of at least 5 necrotic cells were observed. Tumor necrosis (26% of the cases) was associated with increased tumor thickness, high mitotic count, presence of tumor ulceration, and decreased survival. Stratified analyses (univariate and multivariate) with standard microscopic variables indicated the strongest prognostic influence of necrosis in tumors thicker than 4 mm. Notably, in the stratum of pT4 tumors, presence of necrosis was a stronger prognostic predictor than was ulceration. Tumor necrosis was a significant prognostic indicator providing additional information to established predictors of patient outcome in this series of nodular cutaneous melanoma, predominantly among thick tumors (> 4 mm). Presence of necrosis was a stronger indicator for worse outcome compared with ulceration in pT4 tumors.