Atypical Hyperplasia - Ductal and Lobular

Atypical hyperplasia is a term which refers to an accumulation of abnormal cells in the breast tissue. It is not cancer, but can be a pre-cancerous condition where the abnormal cells causing hyperplasia keep dividing in an uncontrolled manner. It may lead to non-invasive or invasive breast cancer in the long term.

People diagnosed with atypical hyperplasia have a higher risk of developing breast cancer in the future than those who don’t have the condition. Hence breast cancer screening and medications to lower the risk of breast cancer are recommended for women with atypical hyperplasia. However, it is worth noting that the majority of women with atypical hyperplasia never go on to develop breast cancer in their lifetime.

There are two types of atypical hyperplasia – ductal and lobular. This indicates the origin of the abnormal cells. ‘Ductal’ means the abnormal cells are detected in one of the ducts through which the breast milk travels to reach the nipple.

‘Lobular’ means the abnormal cell growth is in the lobules, which are the areas in the breast that make milk. While atypical ductal hyperplasia (ADH) increases breast cancer risk in the area where it was found, atypical lobular hyperplasia (ALH) increases the cancer risk in both the breasts.

What Is Atypical Ductal Hyperplasia?

Atypical Ductal Hyperplasia (ADH)

In ADH, the abnormal pattern of cell growth happens in the lactiferous ducts. It is not exactly a pre-cancerous condition, but is still linked to higher breast cancer risk in the future. In fact, patients with ADH have the highest probability of developing invasive cancer compared to patients with all other proliferative breast conditions.

ADH is closely related to the non-invasive malignant ductal carcinoma in situ (DCIS) and may be considered an early version of it. Both conditions indicate that the premalignant cell changes detected are at a very early stage, and the prognosis is good. On histological analysis, features of ADH closely resemble those of low-grade DCIS, but smaller in size. Two key criteria that help distinguish ADH from DCIS are:

1) there is uniform involvement of up to 2 duct spaces of the breast

2) the size of the lesion is under 2 mm

When ADH is detected, the sample tissue removed for biopsy needs to be examined under a microscope. If need be, more tissue may be excised from the surrounding area to confirm the type of abnormal cell growth. If this shows no serious abnormality, no treatment is necessary. Follow-up breast imaging and examinations can be scheduled as part of screening.

Atypical Lobular Hyperplasia (ALH)

Atypical lobular hyperplasia occurs within the breast lobules and is linked to an increased risk of breast cancer in the future. According to current breast tumor classification standards, any excess lobular epithelial cells should be classified under ‘lobular neoplasia’, which includes:

  • ALH
  • lobular carcinoma in-situ (LCIS)
  • pleomorphic lobular carcinoma in-situ (PLCIS)

Although this classification is particularly intended for pathologists, the distinction between these 3 types is usually made in the pathology reports that patients receive. However, the difference between these various types of lobular neoplasia may not be very important in terms of prognosis, treatment, or subsequent risk of developing cancer in the future. A 2003 study reported that invasive lobular carcinoma is 3 times more likely to develop in the same breast in which ALH was diagnosed than in the other breast.

Similar to ADH, in ALH treatment, microscopic examination of sample tissue reveals the cell growth pattern. Based on the results, doctors will decide if more tests are required. Follow up with imaging and physical examination is recommended.


Further Reading

Last Updated: Feb 26, 2019

Susha Cheriyedath

Written by

Susha Cheriyedath

Susha is a scientific communication professional holding a Master's degree in Biochemistry, with expertise in Microbiology, Physiology, Biotechnology, and Nutrition. After a two-year tenure as a lecturer from 2000 to 2002, where she mentored undergraduates studying Biochemistry, she transitioned into editorial roles within scientific publishing. She has accumulated nearly two decades of experience in medical communication, assuming diverse roles in research, writing, editing, and editorial management.


Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Cheriyedath, Susha. (2019, February 26). Atypical Hyperplasia - Ductal and Lobular. News-Medical. Retrieved on July 19, 2024 from

  • MLA

    Cheriyedath, Susha. "Atypical Hyperplasia - Ductal and Lobular". News-Medical. 19 July 2024. <>.

  • Chicago

    Cheriyedath, Susha. "Atypical Hyperplasia - Ductal and Lobular". News-Medical. (accessed July 19, 2024).

  • Harvard

    Cheriyedath, Susha. 2019. Atypical Hyperplasia - Ductal and Lobular. News-Medical, viewed 19 July 2024,


The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
Post a new comment

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.

You might also like...
COVID-19 tied to elevated risk of benign prostatic hyperplasia complications