# Carcinoma with medullary pattern (medullary breast cancer)

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

## TL;DR

Medullary breast cancers are high-grade, triple-negative tumours with a sharp border and a heavy immune-cell infiltrate that, despite looking aggressive, do better than ordinary breast cancers of the same grade. They are linked to BRCA1. Pathologists now call them a medullary pattern of common breast cancer rather than a type of their own.

## Summary

Medullary carcinoma was defined by a circumscribed, syncytial growth pattern, high nuclear grade and a dense lymphoplasmacytic infiltrate; because pathologists agreed poorly on the diagnosis and the molecular profile overlaps basal-like carcinoma, the 5th edition of the WHO classification (2019) reclassified it as invasive breast carcinoma of no special type with medullary pattern, alongside the other patterns of common ductal-origin carcinoma (Cserni 2020; Thomas 2023). Its behaviour is better than its grade suggests: among 12,409 patients in 13 International Breast Cancer Study Group trials, 14-year distant recurrence-free interval was 76 percent for 127 medullary against 64 percent for 8,096 invasive ductal tumours (hazard ratio 0.52) and overall survival 66 against 57 percent (0.75); restricted to ER-negative grade 3 tumours the figures were 89 against 63 percent (0.24) and 74 against 54 percent (0.55) (Huober 2012). Medullary tumours are BRCA1-related (odds ratio for BRCA2 versus BRCA1 carrier status 0.25 in the CIMBA pathology series, Mavaddat 2012), and the claudin-low subtype shows frequent medullary differentiation (Prat 2010). The immune infiltrate is the same feature now scored as stromal tumour-infiltrating lymphocytes across triple-negative disease.

## Fields

- Kind: Cancer
- Last checked: 2026-09-24
- Also known as: Medullary carcinoma of the breast; Medullary breast cancer; Invasive carcinoma of no special type with medullary pattern; Atypical medullary carcinoma; Basal-like carcinoma with medullary features; Invasive breast carcinoma with medullary pattern; Medullary carcinoma; Carcinoma with medullary features; Medullary-like carcinoma; Atypical medullary carcinoma of the breast
- Tags: breast; tnbc; subtype-page
- Group: breast
- Burden: About 1 percent of breast cancers in trial populations: 127 of 12,409 patients in 13 IBCSG trials were recorded as medullary (Huober 2012). The 2019 WHO classification no longer lists it as a separate type.
- Subtypes: Invasive carcinoma of no special type (ductal) with medullary pattern, the 2019 WHO term; Classic medullary carcinoma by the older strict criteria; Atypical medullary carcinoma (older term for tumours meeting some criteria)
- Biomarkers: Triple-negative receptor status with grade 3; Dense lymphoplasmacytic infiltrate (high stromal tumour-infiltrating lymphocytes); Germline BRCA1 (medullary tumours are BRCA1-related)

## 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/medullary-pattern-breast-carcinoma/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/medullary-pattern-breast-carcinoma/#overview
- Types and stages (on the hub): Anatomy, the subtypes and how they differ, how it is staged, and where advanced disease spreads. https://onco.cc/cancers/medullary-pattern-breast-carcinoma/#what-it-is [3 subtypes]
- Symptoms and diagnosis (on the hub): How this cancer shows itself, how the diagnosis is confirmed, and the biomarkers clinicians test for. https://onco.cc/cancers/medullary-pattern-breast-carcinoma/#finding-it [3 biomarkers]
- Treatment (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/medullary-pattern-breast-carcinoma/#treating-it [1 setting]
- Trials and papers (on the hub): Trials recruiting now, the landmark trials, the trials held by this cancer's subtypes, the key papers and what they mean, the latest literature, and the milestones year by year. https://onco.cc/cancers/medullary-pattern-breast-carcinoma/#evidence [1 trial]
- Biology and targets (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/medullary-pattern-breast-carcinoma/#science [1 target]
- Countries and centres (own page): Cases by country, the UK and NHS pathway and other country lenses, the expert centres with trials on record, and the centres named on this cancer's subtypes. https://onco.cc/cancers/medullary-pattern-breast-carcinoma/where-you-are/ [16 UK centres]
- Decisions and support (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/medullary-pattern-breast-carcinoma/#living-with-it [8 questions]
- Pipeline and open problems (own page): Everything in development, the medicines held by this cancer's subtypes, the open problems and what is being done about them, the roadmaps, and what changed on this record. https://onco.cc/cancers/medullary-pattern-breast-carcinoma/coming/
- 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/medullary-pattern-breast-carcinoma/data/ [8 connected records, 1 note]

## Standard of care

- Early disease: As for triple-negative disease of no special type, including germline testing; the medullary pattern is recorded because of its better prognosis but does not change the NICE pathway. ([KEYNOTE-522](https://onco.cc/trials/keynote-522/), [Germline (hereditary) testing](https://onco.cc/technologies/germline-testing/), [Tumour-infiltrating lymphocytes (TILs)](https://onco.cc/terms/tils/))

## Notes

- Two more series, smaller than the trial cohorts above and quoted with their own denominators. In a Shiraz breast centre's 22-year experience, 179 medullary carcinomas among 3,246 patients (5.5 percent of that centre's series) were of higher grade than the 3,067 ductal carcinomas beside them and yet had a more favourable clinical outcome (Iranian Journal of Medical Sciences 2018). 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 of tumours, was an independent prognostic factor and showed good agreement between observers (Modern Pathology 2010). Both are quoted from the series named, and neither is a population figure: with the 2019 definition the pattern is no longer counted separately, so any percentage for how common medullary carcinoma is describes how often it was recognised.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Medullary_breast_carcinoma
- Huober, Ann Oncol 2012: prognosis of medullary breast cancer in 13 IBCSG trials: https://doi.org/10.1093/annonc/mds105
- Cserni, Pathologica 2020: histological type and typing of breast carcinomas and WHO classification changes: https://doi.org/10.32074/1591-951x-1-20
- Thomas, NPJ Breast Cancer 2023: rare subtypes of triple-negative breast cancer: https://doi.org/10.1038/s41523-023-00554-x
- Mavaddat, Cancer Epidemiol Biomarkers Prev 2012: pathology of breast cancers in BRCA1 and BRCA2 carriers (CIMBA): https://doi.org/10.1158/1055-9965.epi-11-0775
- Prat, Breast Cancer Res 2010: phenotypic and molecular characterisation of the claudin-low intrinsic subtype: https://doi.org/10.1186/bcr2635
- Tan et al., Histopathology 2020: the 2019 WHO classification of tumours of the breast (5th edition): https://doi.org/10.1111/his.14091
- Quinn et al., Histopathology 2026;89(2):199 to 218: World Health Organization classification of tumours of the breast, 6th edition 2026: https://doi.org/10.1111/his.70149

## Connected records

- cancers: [BRCA-associated triple-negative breast cancer](https://onco.cc/cancers/brca-associated-tnbc/), [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Immunomodulatory triple-negative breast cancer (IM)](https://onco.cc/cancers/tnbc-immunomodulatory/), [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/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- targets: [BRCA1 / BRCA2 (HRD)](https://onco.cc/targets/brca/)
- terms: [Basal-like breast cancer](https://onco.cc/terms/basal-like/), [Germline BRCA testing criteria for triple-negative breast cancer (UK)](https://onco.cc/terms/germline-brca-testing-criteria-tnbc/), [Nottingham grade (breast cancer grade 1, 2 and 3)](https://onco.cc/terms/nottingham-grade/), [The WHO classification of breast tumours, and what the 6th edition changed](https://onco.cc/terms/who-breast-classification/), [Tumour-infiltrating lymphocytes (TILs)](https://onco.cc/terms/tils/)
- trials: [KEYNOTE-522](https://onco.cc/trials/keynote-522/)
- technologies: [Germline (hereditary) testing](https://onco.cc/technologies/germline-testing/)

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