Classification of benign breast disorders. The ANDI classification based on physiological processes within the normal breast.

Terminology in benign breast conditions has been confused by multiplicity of terms which do not relate accurately to clinical or histological patterns. Further confusion arises because terminology is not based on sound concepts of pathogenesis. The ANDI classification has been put forward as a nomenclature based on pathogenesis to replace the division of benign breast disorders into 'normal' and 'disease'. It recognizes that a spectrum exists for most conditions which extends from normal, through mild abnormality--'aberrations'--to disease. This classification allows precise definition of an individual patient problem in terms of pathogenesis, histology and clinical implications. It has proved helpful in deciding rational clinical management and in teaching the significance of benign breast disorders.