International Academy of Cosmetic Dermatology
A node is a firm lesion that is usually elevated above the skin. It might also be called a knot or lump.
While a cyst represents a sac containing a liquid or semisolid substance, a node contains harder material that cannot be expressed by pressure or through incision and drainage. Examples of a node are prurigo nodularis and erythema nodosum.
Lawrence Charles Parish, MD, MD (Hon)