The two most common clinical conditions in which a hard lump appears on the back of the neck are sebaceous cysts or lipomas. Both sebaceous cysts and lipomas tend to present clinically as lumps with clear borders, tough texture, and relatively good mobility. The simple distinction is that sebaceous cysts usually have blackheads on the surface, while lipomas do not have blackheads on the surface. Since the back of the neck belongs to the back of the neck and the skin layer is thicker, clinical palpation is not very satisfactory and further ultrasound examination is usually required to make a clear diagnosis. After the diagnosis is clear, either sebaceous cyst or lipoma usually requires surgery to remove it completely, and further pathological examination is needed if necessary.