Premenarchal athletic injury to the breast bud as the cause for asymmetry: prevention and treatment.

Some variation in breast size is normal and is common in most women. When this variation becomes large and appreciable asymmetry develops--greater than a one-cup size difference--the asymmetry often disrupts the patient's life. The etiology of most breast asymmetries is unknown; however, current theories on causes include endocrine, iatrogenic, and traumatic injury.