<B>Duct Hyperplasia with Atypia </B>

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Duct Hyperplasia with Atypia

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)
• Either part or all of up to two ducts in one location (or a focus less than 2 mm in diameter) contain cells with all the cytologic and histologic features of duct carcinoma in situ
• Features include loss of polarity to lumen, round "punched-out" lumens, and homogeneity of cells
• Cells may show enlarged, round to oval nuclei and nucleoli

Clinical Correlations:

• Found either by mammography or incidentally
• Increased risk of developing breast carcinoma 4-5x

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