What you’re seeing on your grandpa’s neck is very often something called seborrheic keratosis—a common, benign skin growth that tends to appear after age 50. These spots can look dramatic: brown, black, or tan, with a waxy, “stuck‑on” appearance that can make anyone think of skin cancer. They may show up one by one or in clusters, and can seem to appear almost overnight, especially on the chest, back, scalp, or neck.

Despite their unsettling look, seborrheic keratoses are not cancer and do not turn into cancer. Still, they can closely mimic melanoma, so any spot that changes, bleeds, or looks irregular deserves a doctor’s eye. A clinician can usually recognize them on sight, sometimes with a dermatoscope, and remove bothersome ones by freezing or gentle scraping. The most important step is simple: don’t pick or cut them yourself, and don’t stay silent—have them checked, and replace fear with informed reassurance.