Finding a lump on your neck, back, or behind your ear can be alarming, often triggering worst-case fears. However, most lumps are harmless and caused by common, non-serious conditions.

Lumps can vary in size and cause. Understanding why one appears can help determine whether it’s something minor or something that needs medical attention.

A common cause is an epidermoid cyst. These form when skin cells build up beneath the surface instead of shedding normally, creating a slow-growing bump filled with keratin.