Proliferative nodules with balloon-cell change in a large congenital melanocytic nevus.

The balloon-cell nevus was first described over 100 years ago. Since then, balloon-cell changes of melanocytes have been noted in numerous tumors, including melanoma, blue nevus, and Spitz nevus. Whether these changes reflect cellular deterioration or proliferative changes is a matter of debate. We report a case in which balloon-cell changes were found within proliferative nodules occurring in a large congenital melanocytic nevus.