Table of Contents
Definition / general | Clinical features | Prognostic factors | Case reports | Clinical images | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Cytology images | Positive stains | Negative stains | Molecular / cytogenetics description | Videos | Differential diagnosis | Additional referencesCite this page: Medullary carcinoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/breastmalignantmedullary.html. Accessed July 14th, 2017.
Definition / general
- Well circumscribed, composed of poorly differentiated cells in syncytia or large sheets, with prominent lymphoplasmacytic infiltrate, scant fibrous stroma, no glandular structures, minimal DCIS
- Considered a type of basal-like carcinoma (Breast Cancer Res 2007;9:R24, Am J Surg Pathol 2007;31:501)
- "Medulla" refers to soft structure of marrow (tumors are often soft)
Clinical features
- Uncommon, < 1% of invasive breast carcinomas
- Usually < 50 years old, often < 35 years old, common in Japanese, associated with BRCA1 mutations
- More activated cytotoxic lymphocytes than poorly differentiated ductal carcinomas (Mod Pathol 1999;12:1050, Mod Pathol 2008;21:1101)
Prognostic factors
- Slightly better prognosis than invasive ductal carcinoma NOS, even though high grade, aneuploid, ER / PR negative, p53 positive and high proliferation rates (Hum Pathol 1988;19:1340, Int J Radiat Oncol Biol Phys 2005;62:1040)
- Better prognosis may be due to prominent inflammation (Eur J Cancer 2009;45:1780, Mod Pathol 2010;23:1357)
Case reports
- 58 year old woman with synchronous bilateral medullary carcinoma (J Cancer Res Ther 2012;8:129)
Gross description
- Well circumscribed, often large, resembles fibroadenoma but without whorls
- Soft, fleshy, tannish gray
- No desmoplasia
- Easy to cut, large areas of necrosis and hemorrhage
Gross images
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Microscopic (histologic) description
- Indistinct cell borders (syncytial growth) making up 75%+ of tumor with large pleomorphic tumor cells containing large nuclei, prominent nucleoli, numerous mitotic figures; peripheral cells are more eosinophilic
- Prominent lymphoplasmacytic infiltrate at periphery composed of T cells and IgA plasma cells
- Pushing borders / well circumscribed
- Classify as medullary carcinoma if tumor has above three features
- Classify as atypical medullary carcinoma (or infiltrating ductal carcinoma) if tumor has only 2 of 3 features listed above (atypical medullary carcinoma has similar prognosis as ductal carcinoma NOS)
- Other features:
- Sparse stroma
- Variable spindle cell or squamous metaplasia, occasional bizarre tumor giant cells and extensive necrosis
- No / minimal glandular differentiation, no intraductal growth or DCIS, no mucin, no calcification
Microscopic (histologic) images
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AFIP images:
AFIP - Atypical medullary carcinoma:
Images hosted on other servers:
Flickr images:
Images hosted on PathOut server:
AFIP images:
AFIP - Atypical medullary carcinoma:
Images hosted on other servers:
Flickr images:
Cytology description
- Cellular smears
- Tumor cells in loosely cohesive sheets and single cells
- Moderate / marked nuclear pleomorphism and nuclear irregularities, mixed with mononuclear inflammation (Diagn Cytopathol 2007;35:408, Acta Cytol 2009;53:165)
Negative stains
Molecular / cytogenetics description
- Microsatellite instability is uncommon, in contrast to medullary colonic tumors (Am J Clin Pathol 2001;115:823)
- Similar genetic alterations as basal-like carcinomas
- Usually aneuploid
- Associated with BRCA1 mutations
Videos
Histopathology Breast—Medullary carcinoma
Differential diagnosis
- Collision tumor of invasive ductal NOS and MALT lymphoma: see Arch Pathol Lab Med 2004;128:99
- Lymphoepithelioma-like carcinoma: has infiltrative borders
- Lymph node in axillary tail: not circumscribed and may not be syncytial
- Undifferentiated ductal carcinoma: lacks prominent lymphoplasmacytic infiltrate, has infiltrative borders
Additional references





























