Invasive breast carcinoma of no special type and variants


Editorial Board Member: Julie M. Jorns, M.D.
Deputy Editor-in-Chief: Gary Tozbikian, M.D.
Shannon Mingo Welter, M.D.
Emil Racila, M.D.

Last author update: 25 April 2022
Last staff update: 25 April 2022

Copyright: 2003-2023,, Inc.

PubMed Search: Invasive breast carcinoma of no special type with medullary pattern

Shannon Mingo Welter, M.D.
Emil Racila, M.D.
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Page views in 2023 to date: 12,508
Cite this page: Welter SM, Racila E. Medullary. website. Accessed June 4th, 2023.
Definition / general
  • Medullary pattern is a histological pattern that can be applied to an invasive breast carcinoma of no special type that contains pushing borders, syncytial growth, high grade nuclei and prominent lymphoid infiltrate
  • Represents one end of the spectrum of tumor infiltrating lymphocyte (TIL) rich invasive breast carcinomas of no special type rather than a distinct morphological subtype
Essential features
  • Medullary pattern of invasive breast carcinoma no special type has 4 characteristic histological features (ideally, all 4 should be present for the diagnosis):
    • Pushing border
    • Syncytial growth pattern
    • High grade nuclei
    • Prominent lymphoid infiltrate
  • Preferred term according to WHO: invasive breast carcinoma of no special type with medullary pattern
  • Historically described as medullary carcinoma, atypical medullary carcinoma, medullary features
ICD coding
  • ICD-O: 8500/3 - infiltrating duct carcinoma, NOS
  • ICD-11: 2C61.0 & XH7KH3 - invasive carcinoma of breast, NOS & infiltrating duct carcinoma, NOS
  • Often present earlier in life, median age of 53 (45 - 62) years (JAMA Netw Open 2021;4:e214123)
  • Rare: less than 5% of all invasive breast cancers
  • Breast
Clinical features
  • Younger age
  • Soft, palpable, circumscribed mass
  • May have lymphadenopathy (due to hyperplasia rather than metastasis, which is uncommon)
  • Diagnostic steps are identical to invasive breast carcinoma (screening mammogram, diagnostic mammogram, ultrasound, core biopsy, etc.)
Radiology description
  • Round, oval or lobulated mass on mammography
  • Hypoechoic mass on ultrasound with thick echogenic halo
Radiology images

Contributed by Julie M. Jorns, M.D. and Mark R. Wick, M.D.



Prognostic factors
  • Prognostic factors identical to invasive breast carcinoma of no special type: patient age, tumor histological grade, tumor stage, lymphovascular invasion, ER, PR and HER2 status, molecular subtype
  • Additional prognostic factors:
Case reports
  • Identical to treatment options for invasive breast carcinoma of no special type with considerations for targeted therapy based on ER, PR, HER2 status
  • Tumor infiltrating lymphocytes do not alter therapy currently
Gross description
  • Well circumscribed, 2 - 3 cm in size, soft and fleshy (may resemble fibroadenoma)
  • Homogenous with white to gray appearance
Gross images

Contributed by Mark R. Wick, M.D.

White mass

Microscopic (histologic) description
  • Well circumscribed pushing border
  • Cells in syncytial growth pattern with no glandular structures
  • High histologic grade, high grade nuclei with prominent nucleoli
  • Prominent tumor infiltrating lymphocyte infiltrate
Microscopic (histologic) images

Contributed by Shannon M. Welter, M.D. and Julie M. Jorns, M.D.

Circumscribed tumor

Prominent lymphoid infiltrate

Syncytial growth pattern

Stromal lymphocytes

High grade nuclei

High grade nuclei

Numerous mitotic figures

Biopsy site and circumscription

Syncytial growth and lymphoplasmacytic infiltrate


Virtual slides

Images hosted on other servers:
Missing Image

Breast cancer with medullary pattern

Cytology description
  • Hypercellular specimen
  • Numerous isolated cells and loose clusters
  • Markedly enlarged, vesicular nuclei
  • Prominent, often irregular macronucleolus
  • Many lymphocytes and some plasma cells
Positive stains
Negative stains
Molecular / cytogenetics description
  • Genomic instability is common
  • Majority of these tumors fall within the basal-like molecular profile
  • Approximately 15% of tumors in BRCA1 mutation carriers are classified as invasive breast carcinoma with medullary pattern (J Natl Cancer Inst 1998;90:1138)
Sample pathology report
  • Breast, right, segmental mastectomy:
    • Invasive breast carcinoma of no special type with medullary pattern (see synoptic report)
    • Carcinoma contains 90% stromal tumor infiltrating lymphocytes
Differential diagnosis
Board review style question #1

The tumor in the above image is found in the breast of a 45 year old woman. The tumor was round and soft on palpation and had pushing borders on microscopy. What is the most likely diagnosis?

  1. Ductal carcinoma in situ
  2. Invasive breast carcinoma with medullary pattern
  3. Invasive lobular carcinoma
  4. Secretory carcinoma
Board review style answer #1
B. Invasive breast carcinoma with medullary pattern

Comment Here

Reference: Invasive breast carcinoma of no special type with medullary pattern
Board review style question #2
Which of the following is a feature of invasive breast carcinoma with medullary pattern?

  1. Extensive surrounding ductal carcinoma in situ
  2. Low histologic grade
  3. Present as calcifications on mammography
  4. Prominent lymphocytic infiltrate
Board review style answer #2
Board review style question #3

This breast tumor most often falls into which molecular profile?

  1. Basal-like
  2. HER2 enriched
  3. Luminal A
  4. Luminal B
Board review style answer #3
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