Definition/General
Introduction:
Sclerosing adenosis is a benign proliferative breast lesion characterized by a proliferation of glandular and myoepithelial cells, associated with stromal sclerosis
It can mimic invasive carcinoma both clinically and mammographically.
Origin:
It arises from the terminal duct-lobular unit (TDLU)
It is a type of adenosis, which is a general term for an increase in the number of glands.
Classification:
Sclerosing adenosis is classified as a benign proliferative breast lesion without atypia
It is a component of fibrocystic changes.
Epidemiology:
It is a common finding in breast biopsies, especially in the perimenopausal age group.
Clinical Features
Presentation:
It can present as a palpable mass or be detected on mammography as a spiculated mass or calcifications, raising suspicion for malignancy.
Symptoms:
It can be associated with breast pain (mastalgia).
Risk Factors:
Not applicable.
Screening:
Mammographically, it can mimic invasive carcinoma, showing a spiculated mass, architectural distortion, or microcalcifications.
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Gross Description
Appearance:
It may not have a distinct gross appearance
When it forms a mass, it is typically a firm, rubbery, ill-defined lesion.
Characteristics:
The cut surface is gray-white and fibrous.
Size Location:
Usually small, but can form a palpable mass.
Multifocality:
Can be multifocal.
Microscopic Description
Histological Features:
The lesion is characterized by a proliferation of small, compressed glands in a dense, sclerotic stroma
The glands are arranged in a swirling or whorled pattern
The key feature is the preservation of the lobulocentric architecture and the presence of a myoepithelial cell layer.
Cellular Characteristics:
The epithelial cells are bland, with small, uniform nuclei
The myoepithelial cells are also present and can be prominent.
Architectural Patterns:
The glands are often distorted and compressed by the sclerotic stroma, which can mimic the infiltrative pattern of invasive carcinoma.
Grading Criteria:
This is a benign lesion.
Immunohistochemistry
Positive Markers:
The myoepithelial cell layer is highlighted by myoepithelial markers such as p63, calponin, and smooth muscle actin (SMA)
The epithelial cells are positive for cytokeratins.
Negative Markers:
Not applicable.
Diagnostic Utility:
IHC for myoepithelial markers is crucial to differentiate sclerosing adenosis from invasive carcinoma, especially tubular carcinoma
The presence of a continuous myoepithelial layer confirms the benign nature of the lesion.
Molecular Subtypes:
Not applicable.
Molecular/Genetic
Genetic Mutations:
Not applicable.
Molecular Markers:
No specific molecular markers are routinely used for diagnosis.
Prognostic Significance:
Sclerosing adenosis is associated with a small increased risk (about 1.5-2 fold) of developing invasive breast cancer.
Therapeutic Targets:
No specific treatment is required
Management is focused on excluding malignancy.
Differential Diagnosis
Similar Entities:
Invasive ductal carcinoma, especially tubular carcinoma
Radial scar.
Distinguishing Features:
Tubular carcinoma lacks a myoepithelial layer around the infiltrating tubules
A radial scar has a central fibroelastotic core and entrapped glands, but the overall architecture is different.
Diagnostic Challenges:
The main challenge is distinguishing sclerosing adenosis from invasive carcinoma on small biopsies
The distorted glands can be very suspicious
IHC for myoepithelial markers is essential in these cases.
Rare Variants:
Not applicable.
Sample Pathology Report
Template Format
Sample Pathology Report
Complete Report: This is an example of how the final pathology report should be structured for this condition.
Specimen Information
[specimen type], measuring [size] cm in greatest dimension
Diagnosis
[diagnosis name]
Classification
Classification: [classification system] [grade/type]
Histological Features
Shows [architectural pattern] with [nuclear features] and [mitotic activity]
Size and Extent
Size: [X] cm, extent: [local/regional/metastatic]
Margins
Margins are [involved/uninvolved] with closest margin [X] mm
Lymphovascular Invasion
Lymphovascular invasion: [present/absent]
Lymph Node Status
Lymph nodes: [X] positive out of [X] examined
Special Studies
IHC: [marker]: [result]
Molecular: [test]: [result]
[other study]: [result]
Final Diagnosis
Final diagnosis: [complete diagnosis]