<B>Duct Hyperplasia (Non-atypical) </B>

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Duct Hyperplasia (Non-atypical)

Etiology:

• Secondary to an irregular response by breast tissue to hormonal stimuli

Pathogenesis:

• May be due to relative or absolute excess of estrogen, decrease in progesterone, or abnormal response to either hormone by breast tissue

Epidemiology:

• Reproductive age women

General Gross Description:

• May be associated with microcalcifications within the lumens
• Gross findings may be of fibrocystic change

General Microscopic Description:

• Ducts exhibit more than the usual two layer epithelium (inner cuboidal to columnar cells; outer layer of myoepithelium)
• May be a solid mass of cells filling the ducts
• May show papillary infoldings (with fibrovascular cores termed papillomatosis)
• Maintain intact myoepithelial layer
• Slit-like spaces between cells
• Cells retain orientation toward lumen and/or slits
• Microcalcifications within ducts

Clinical Correlations:

• Found either by mammography or incidentally
• In the absence of atypia increased risk of developing breast carcinoma 1.5-2x

References:
• Cotran RS, Kumar V, Robbins SL. Robbins Pathologic Basis of Disease 5th edition. W.B. Saunders, Philadelphia, 1994, pp.1093-1097.