# Invasive breast carcinoma with medullary pattern (medullary carcinoma)

Source: https://onco.cc/cancers/breast-carcinoma-medullary-pattern/  
OnCo record `breast-carcinoma-medullary-pattern` (Cancer). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Medullary carcinoma is a form of breast cancer with high-grade cells growing in sheets and a dense crowd of immune cells around them. It looks alarming under the microscope and is usually triple-negative, yet it has a better outlook than other triple-negative cancers. Since 2019 it is classed as invasive breast cancer with a medullary pattern and treated as triple-negative disease.

## Summary

The 2019 WHO classification abandoned medullary carcinoma and atypical medullary carcinoma as separate types because of poor reproducibility, and instead recognises a medullary pattern within invasive breast carcinoma of no special type, treated as one end of the spectrum of tumour-infiltrating lymphocyte-rich triple-negative cancers (Tan 2020). Its histological features are syncytial sheets of high-grade cells, a prominent lymphoplasmacytic infiltrate, a pushing margin and absent gland formation. In 165 triple-negative basal-like carcinomas, prominent inflammation and anastomosing sheets in at least 30 percent of the tumour were each associated with better prognosis, their combination (a simplified medullary-like definition) was present in 17 percent and was an independent prognostic factor with good inter-observer agreement (Modern Pathology 2010). In a Shiraz series of 179 medullary against 3,067 ductal carcinomas, the medullary group had higher grade yet a more favourable clinical outcome (Iranian J Med Sci 2018). Medullary features are over-represented in BRCA1 carriers.

How it differs from its parent: it is the triple-negative pattern in which the immune infiltrate predicts a good outcome, and its pathology overlaps with the immunomodulatory subtype on the triple-negative page.

How common: 5.5 percent of one centre's series (Iranian J Med Sci 2018), but with the 2019 definition it is no longer counted separately.

Treatment: as triple-negative breast cancer, following the parent's early and metastatic triple-negative pages (chemotherapy with pembrolizumab in early disease, and the checkpoint and antibody-drug conjugate pathways when advanced); there is no trial in the medullary pattern itself.

## Fields

- Kind: Cancer
- Last checked: 2026-09-24
- Also known as: Medullary carcinoma; Medullary breast carcinoma; Medullary carcinoma of the breast; Atypical medullary carcinoma; Carcinoma with medullary features; Medullary-like carcinoma
- Tags: subtype-page; wave4; breast
- Group: breast
- Burden: 179 of 3,246 patients (5.5 percent) in a 22-year Iranian breast centre series (Iranian J Med Sci 2018); medullary-like features were present in 17 percent of 165 basal-like triple-negative carcinomas (Modern Pathology 2010). Population figures are lower and depend on the definition used.
- Subtypes: Invasive carcinoma of no special type with medullary pattern, triple-negative (basal-like) with high lymphocyte infiltrate; Medullary pattern in BRCA1-associated breast cancer; Former atypical medullary carcinoma (partial features)
- Biomarkers: Triple-negative receptor status with basal markers (CK5/6, CK14, CK17, EGFR); Tumour-infiltrating lymphocytes (prominent); BRCA1 germline testing; PD-L1 for metastatic disease

## Sections of this record

The page is a hub with ten sections in reading order; large sections have their own page. The same plan as JSON: https://onco.cc/api/v1/cancers/breast-carcinoma-medullary-pattern/sections.json

- Overview (on the hub): The TL;DR, the family this cancer belongs to, the organ, who gets it and what the state of the art is. https://onco.cc/cancers/breast-carcinoma-medullary-pattern/#overview
- What it is (on the hub): Anatomy, the subtypes and how they differ, how it is staged, and where advanced disease spreads. https://onco.cc/cancers/breast-carcinoma-medullary-pattern/#what-it-is [3 subtypes]
- Finding it (on the hub): How it shows itself, how it is confirmed, what screening exists, and the biomarkers clinicians test for. https://onco.cc/cancers/breast-carcinoma-medullary-pattern/#finding-it [4 biomarkers]
- Treating it (on the hub): The standard of care by setting, the medicines, surgery and radiotherapy named in it, and the regimens behind them. https://onco.cc/cancers/breast-carcinoma-medullary-pattern/#treating-it [1 setting]
- Evidence (on the hub): Trials recruiting now, the landmark trials, the key papers and what they mean, the latest literature, and the milestones year by year. https://onco.cc/cancers/breast-carcinoma-medullary-pattern/#evidence
- The science (on the hub): The molecular landscape: the targets and how often each appears, the pathways, the mechanics stages and the preclinical models. https://onco.cc/cancers/breast-carcinoma-medullary-pattern/#science [1 target]
- Where you are (own page): Cases by country, the UK and NHS pathway and other country lenses, and the expert centres with trials on record. https://onco.cc/cancers/breast-carcinoma-medullary-pattern/where-you-are/
- Living with it (on the hub): The decisions you may face, the aids that walk through them, the warnings on record, the first sixty days and the questions to ask. https://onco.cc/cancers/breast-carcinoma-medullary-pattern/#living-with-it [8 questions, 3 red cards]
- What is coming (own page): Everything in development, the open problems and what is being done about them, the roadmaps, and what changed on this record. https://onco.cc/cancers/breast-carcinoma-medullary-pattern/coming/ [1 medicine]
- Data (own page): Every connected record, the notes, the JSON, Markdown and RDF twins, and where the record came from and when it was checked. https://onco.cc/cancers/breast-carcinoma-medullary-pattern/data/ [4 connected records]

## Standard of care

- All stages: Treated as triple-negative breast cancer on the parent's early and metastatic pages. ([Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/), [Early triple-negative breast cancer](https://onco.cc/cancers/tnbc-early/), [Metastatic triple-negative breast cancer](https://onco.cc/cancers/tnbc-metastatic/), [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/))

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Medullary_breast_carcinoma
- Tan 2020, Histopathology: the 2019 WHO classification of tumours of the breast: https://doi.org/10.1111/his.14091
- Modern Pathology 2010: medullary features and prognosis in 165 triple-negative basal-like carcinomas: https://doi.org/10.1038/modpathol.2010.123
- Iranian J Med Sci 2018: medullary breast carcinoma and invasive ductal carcinoma, 22-year series: https://doi.org/10.30476/ijms.2017.40545

## Connected records

- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Early triple-negative breast cancer](https://onco.cc/cancers/tnbc-early/), [Invasive breast carcinoma of no special type (invasive ductal carcinoma)](https://onco.cc/cancers/invasive-breast-carcinoma-no-special-type/), [Metaplastic breast carcinoma](https://onco.cc/cancers/metaplastic-breast-carcinoma/), [Metastatic triple-negative breast cancer](https://onco.cc/cancers/tnbc-metastatic/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- drugs: [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/)

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JSON: https://onco.cc/api/v1/entities/breast-carcinoma-medullary-pattern.json