Significance of Primary Melanoma Regression on Local Infiltrate and Outcome.

INTRODUCTION

The characteristics and the prognostic value of regression in primary melanomas are controversial.

OBJECTIVES

To further characterize "hot" and "cold" tumor's stromas and to investigate the association between dermoscopy, pathology, and the prognostic implications of regression.

METHODS

A 14-year-collection-based retrospective analysis was carried out on 40 patients with confirmed regressive melanomas.

RESULTS

The extent of regression in dermoscopy was associated with the stage of the regression (P = 0.05) and with the MelanA patterns in histology (P = 0.02). Blue-gray and gray-brown color of the peppering (P = 0.01), and the eccentric, multifocal character of the dermoscopic regression (P = 0.05) were associated with "hot" stromas (CD8+, Granzym B+). Focal histologic regression (regressing melanomas) was associated with a good outcome (P < 0.001), while a complete regression (regressed melanomas) was associated with melanoma-related death (P < 0.001). "Hot" stromas (CD8 were significantly associated with survival at 10 years (P = 0.044), while "hot" stromas (Granzyme B) were associated with the locoregional extension (P = 0.016), and the initial distant metastasis (P = 0.016).

CONCLUSIONS

Dermoscopic features of regression in primary melanomas were associated with the stage of regression, its extent, and the "hot" or "cold" nature of the tumor stroma, with prognostic implications.