Breast Epithelial Hyperplasia

Epithelial hyperplasia is benign proliferative breast lesion which arising as an unexpected new growth of epithelial cells.

Talking Moose
Talking Moose
Too many cells. You’re welcome.


Sometimes epithelial hyperplasia is referred to as ‘intraductal breast hyperplasia’ or possibly ‘breast hyperplasia of the usual type’. The lesion has also commonly been referred to as ‘epitheliosis’. Sometimes epithelial hyperplasia has been referred to as papillomatosis as well.

Breast epithelial hyperplasia may occur within a duct, ductule, or a lobule. However, because there can be many variations in presentation, likely due to the influence of various hormones, the distinction between ductal and lobular epithelial hyperplasia can be quite subjective.

epithelial breast hyperplasia (usual type)

Dr. Halls Dr. Halls
The rounded shapes with dark purple rims, are ducts. There’s too many light-purple cells inside these ducts.


Histological features common to breast epithelial hyperplasia

Benign epithelial hyperplasia of the breast will often appear as parallel or ‘streaming’ arrangement of central cells featuring indistinct cell borders. Cells will often have a granular and ‘acidophilic’ cytoplasm. Nuclei tend to be oval and normochromatic and with a slight overlap. Nucleoli tend to be small and indistinct. Frequently, myoepithelial cells are also present. Apocrine metaplasia may also be variably present, and one sometimes finds either intraluminal or stromal calcification. Necrosis is rare. Cell mitoses are generally either absent or extremely minimal, and there will generally be no other atypical features of any kind.

Breast epithelial hyperplasia can be considered on a spectrum

The number of ‘layers’ of neoplastic cells is often used as an informal means of distinguishing different degrees of hyperplasia. When there are two to four new epithelial cell layers, this might be called mild hyperplasia, (which has no increased risk for breast cancer development). When there are greater than four layers the lesion might be termed moderate breast hyperplasia, which does increase risk for breast cancer between 1.5 to 2 times. (This increased risk is thought to be higher for women over 50). When the new layers of neoplastic epithelial cells are so prevalent as to virtually fill the breast duct completely, the lesion might be termed florid hyperplasia, which also increases risk of future breast cancer development up to two times.

Dr. Halls Dr. Halls
That first picture is ‘florid’ hyperplasia, because the extra cells completely filled the duct.


‘Typical’ breast epithelial hyperplasia has only a slight increased risk for breast cancer development

It still remains unclear whether or not epithelial hyperplasia is a completely benign condition, or whether or not it may undergo malignant change into carcinoma. About 26% of cases of epithelial hyperplasia show some atypical features.


  1. Mak , A., Field, AS. Positive predictive value of the breast FNAB diagnoses of epithelial hyperplasia with atypia, papilloma, and radial scar. Diagnostic Cytopathology (2006), 34(12):818-23.
  2. Inai, K., Yamamoto, A., Arihiro, K., Khatun, N., Kurihara, K. and Takeda, S. (1992), Epithelial Hyperplasia of the Breast: Comparison of Incidence between Cases of Breast Carcinoma and Control Autopsy Specimens with Immunohistochemical Observation of Blood Group Antigens. Pathology International, 42: 193–200.
  3. Papantoniou VJ, Sotiropoulou EK, Valsamaki PN, Tsaroucha AG, Sotiropoulou MG, Ptohis ND, Stipsanelli AJ, Dimitrakakis KE, Marinopoulos SG, Tsiouris ST, Antsaklis AJ. Reduced uptake of the proliferation-seeking radiotracer technetium-99m-labelled pentavalent dimercaptosuccinic acid in a 47-year-old woman with severe breast epithelial hyperplasia taking ibuprofen: a case report. J Med Case Reports.(March 2010) 17;4:89.
  4. Harada O, Hoe R, Lin J, Thike AA, Jara-Lazaro AR, Petersson F, Tan PH. Intranuclear inclusions in epithelial cells of benign proliferative breast lesions. J Clin Pathol. (Jun 2011)

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