Organ Systems, Breast

Breast – Usual Type Epithelial Hyperplasia (UTH)

Non-neoplastic luminal proliferation of ductal epithelial and myoepithelial cells, which can fill and expand ductal strucutures.  The morphology shows a mixed cellularity pattern with overlapping nuclei, which often have a “streaming” appearance.  In challenging cases immunohistochemistry can help differentiated these lesions from ADH or DCIS.
 
If present only focally, there is not an increased risk of breast carcinoma.  However, moderate to florid usual type hyperplasia is associated with a 1.5-2X increased relative risk of breast carcinoma.
 
 
Breast - Usual Type Hyperplasia
Usual type hyperplasia of the breast showing an intraductal proliferation of epithelial and myoepithelial cells with overlapping nuclei and streaming.
Breast lesions and risk of developing an invasive carcinoma
Breast Cancer Risk Chart
Breast Cancer Risk Chart
References

Kumar, Vinay, Abul K. Abbas, and Jon C. Aster. Robbins and Cotran Pathologic Basis of Disease. Ninth edition. Philadelphia, PA: Elsevier/Saunders, 2015.