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Medullary Carcinoma – Invasive Breast Cancer


Updated June 26, 2014

Overview of Medullary Carcinoma:

Medullary carcinoma of the breast is a less common form of invasive breast cancer. It is a type of invasive ductal carcinoma (IDC) and takes it name from its color, which is close to the color of brain tissue, or medulla. It starts in your milk ducts, with large cancer cells that look very different from healthy cells. These medullary carcinoma cells tend to form a clear boundary between the tumor and healthy tissue right next to them. This type of tumor shows up well on a mammogram.

Medullary Carcinoma is not a Common Diagnosis:

This type of breast cancer is found in only 3 to 5% of all breast cancers diagnosed. It is quite difficult to distinguish from invasive ductal carcinoma and is usually treated the same as IDC. Medullary carcinoma has been found in about 5% of breast cancer diagnoses.

Signs and Symptoms:

Medullary carcinoma of the breast may not always feel like a lump, but rather, like a thick, spongy area of breast tissue. This type of breast cancer can produce swelling from within your breast. Since the cells for medullary carcinoma are large and tend to stay together and expand in one place, the tumor may feel rather smooth-sided, like a breast cyst. Have any lump or swelling in your breast checked out by a health professional.

Tests Used to Diagnose Medullary Carcinoma:

A mammogram will show a medullary carcinoma breast tumor quite well. The clear-edged border of the tumor will set it apart from surrounding healthy tissue. If there is still some doubt, a breast ultrasound may be done as well. A tissue sample taken by open surgical or stereotactic breast biopsy, however, will give a conclusive diagnosis.

Prognosis for Medullary Carcinoma:

Medullary carcinoma tends to be a high-grade (fast-growing) type of breast cancer but usually does not spread to your lymph nodes as often as other types of invasive breast cancer. After treatment, the 1-year survival rate for medullary carcinoma is 92%, which is very good.


Medullary carcinoma can be successfully treated in most cases. Even though tumors may become large, they seldom metastasize (spread) and respond to treatment well. Treatments may include:

American Cancer Society. What is Breast Cancer? Invasive (or infiltrating) Ductal Carcinoma. Revised: 09/13/2007.

The Relatively Favorable Prognosis Of Medullary Carcinoma Of The Breast. Oliver S. Moore, Jr., M.D., And Frank W. Foote, Jr., M.D. Cancer, Volume 2, Issue 4 (p 635-642). Published Online: 23 Jun 2006.

Modern Pathology (2005) 18, 26–35, advance online publication, 27 August 2004; doi:10.1038/modpathol.3800255. Estrogen receptor-negative breast carcinomas: a review of morphology and immunophenotypical analysis.

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