44291 Population-level data reveals prognostic factors and contextualizes outcomes of malignant blue nevus

Background: Blue nevi are dermally-based nevi comprised of pigmented dendritic cells, macrophages, and spindled melanocytes. Malignant blue nevus (MBN) can arise from an existing blue nevus or de novo as a melanoma resembling a blue nevus. The majority of literature on MBN consists of case reports or series and there is a paucity of population-level data. A retrospective cohort analysis was conducted using the SEER database between 1976-2016. We identified 76 patients with a diagnosis of MBN over the 40-year period.