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Medullary Carcinoma of the Breast

New Right Breast Nodule in 62F • Xray of the Week 2016 • Week #29

This 62 year old female presented with a new right breast nodule. Mammogram and ultrasound were done. The patient had an ultrasound guided biopsy of the nodule, and subsequent excision. What rare type of breast cancer could this be?

Figure 1. Left 2 images: CC Mammogram, shows a nodule with indistinct margins in the right breast medially.

Figure 1. Right 2 images: MLO Mammogram, shows a nodule with indistinct margins in the right breast inferiorly.

Figure 2. Left image: Mammogram spot compression view, shows the nodule with indistinct margins in the right breast medially(red arrow).

Figure 2. Middle and right images: Ultrasound images show a hypoechoic right breast nodule with angular margin (red arrow), which is also taller than wide.

Ultrasound biopsy was performed, followed by excision of the nodule and pathology was medullary breast cancer [Figs.3-4.]

Figure 3. Low power view of medullary carcinoma with well circumscribed, "pushing" border. Histology images courtesy of Dennis Kasimian, MD. Chair of Pathology at Valley Presbyterian Hospital - Van Nuys, CA, USA.

Figure 4. High power views.

A: Syncytial growth of large pleomorphic cells with indistinct cell borders, large vesicular nuclei containing prominent nucleoli and numerous mitoses.

B: Characteristic prominent lymphoplasmacytic inflammatory infiltrate at the periphery of the tumor. Histology images courtesy of Dennis Kasimian, MD. Chair of Pathology at Valley Presbyterian Hospital - Van Nuys, CA, USA.

Medullary breast cancer is a rare form of breast cancer, comprising less than 2% of all breast tumors (1-3). The cancer tends to occur in younger patients, with a mean age at presentation of 46-54. The masses may be well circumscribed or have ill-defined margins (1-3). MRI is nonspecific usually with an oval or lobular shaped mass and rim enhancement with or without enhancing internal septations (4). Of note, ultrasound with a taller than wide appearance has a positive predictive value (PPV) for malignancy of 81% and angular margin on ultrasound has a PPV of 68% (5). Pathologically, the World Health Organization criteria for diagnosis is “a well circumscribed carcinoma composed of poorly differentiated cells with scant stroma and prominent lymphoid infiltration” (6,7). The classic presentation of medullary carcinoma involves a syncytial growth pattern of poorly-differentiated tumor cells with a high mitotic rate (6,7) [Figs.3-4.]. Syncytial pattern indicates a multinucleated mass of cytoplasm that is not separated into individual cells. (7) Although medullary breast cancer has a better prognosis than invasive ductal carcinoma, the nodules may rapidly enlarge (1-4).

Related cases:

Invasive Ductal Carcinoma of the Breast in 27 Year Old

Phyllodes Tumor


1. Harvey JA. Unusual breast cancers: useful clues to expanding the differential diagnosis. Radiology. 2007;242 (3): 683-94.

2. Meyer JE, Amin E, Lindfors KK et-al. Medullary carcinoma of the breast: mammographic and US appearance. Radiology. 1989;170 (1): 79-82.

3. Yoo JL, Woo OH, Kim YK et-al. Can MR Imaging contribute in characterizing well-circumscribed breast carcinomas? Radiographics. 2010;30 (6): 1689-702

4. Jeong SJ, et al. Medullary Carcinoma of the Breast: MRI Findings American Journal of Roentgenology. 2012;198:

5. Stavros AT, Thickman D, Rapp CL et-al. Solid breast nodules: use of sonography to distinguish between benign and malignant lesions. Radiology. 1995;196 (1): 123-34.

6. Rosen PP. Medullary carcinoma. In: Rosen's breast pathology. Philadelphia, Pa: Lippincott-Raven, 1997; 355–374.

7. Pedersen L, Schiødt T, Holck S, Zedeler K. The prognostic importance of syncytial growth pattern in medullary carcinoma of the breast. APMIS. 1990 Oct;98(10):921-6.

Kevin M. Rice, MD is the President of Global Radiology CME

Dr. Rice serves as the Chair of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a radiologist with Renaissance Imaging Medical Associates. Dr. Rice has made several media appearances and as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015 Dr. Rice founded Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field.

Follow Dr. Rice on Twitter @KevinRiceMD

All Posts by Kevin M. Rice, MD

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