When cancer cells enter the leptomeninges, which are part of the membrane that covers the brain and spinal cord, it can turn into a type of metastasis known as leptomeningeal disease (LMD).

“I describe it as a snow globe. Cancer cells can float around and can form new colonies throughout the leptomeninges of the brain and spine,” says Isabella Glitza Oliva, M.D., Ph.D., director of the Melanoma Leptomeningeal Disease Program at...