Definition/General
Introduction:
A fibroadenoma with atypia is a fibroadenoma that contains foci of atypical ductal hyperplasia (ADH) or atypical lobular hyperplasia (ALH) within its epithelial component.
Origin:
The atypia arises within the epithelial component of the fibroadenoma.
Classification:
It is a subtype of complex fibroadenoma.
Epidemiology:
Atypia is found in a small percentage of fibroadenomas.
Clinical Features
Presentation:
Presents as a painless, firm, mobile, well-circumscribed, rubbery mass, similar to a simple fibroadenoma.
Symptoms:
A painless, mobile lump is the most common symptom.
Risk Factors:
There are no well-established risk factors.
Screening:
On mammography, they appear as a well-circumscribed, oval mass.
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Gross Description
Appearance:
A well-circumscribed, encapsulated, firm, gray-white mass.
Characteristics:
The gross appearance is indistinguishable from a simple fibroadenoma.
Size Location:
Size is variable.
Multifocality:
Can be multiple.
Microscopic Description
Histological Features:
The lesion is a fibroadenoma with foci of ADH or ALH
The atypical proliferation is confined to the epithelial component of the fibroadenoma.
Cellular Characteristics:
The atypical cells show features of ADH (monotonous proliferation, cribriform patterns) or ALH (discohesive cells, loss of E-cadherin).
Architectural Patterns:
The background is that of a fibroadenoma.
Grading Criteria:
This is a benign lesion, but the presence of atypia is a significant finding.
Immunohistochemistry
Positive Markers:
The IHC profile of the atypical component is similar to that of ADH or ALH.
Negative Markers:
Not typically required for diagnosis.
Diagnostic Utility:
IHC for E-cadherin can be used to distinguish between ductal and lobular atypia.
Molecular Subtypes:
Molecular subtyping is not relevant for this benign condition.
Molecular/Genetic
Genetic Mutations:
Not well characterized.
Molecular Markers:
No specific molecular markers are routinely used for diagnosis.
Prognostic Significance:
A fibroadenoma with atypia is associated with an increased risk of subsequent breast cancer, similar to that of ADH or ALH in the absence of a fibroadenoma.
Therapeutic Targets:
Management may involve surgical excision to ensure the atypical focus is completely removed and to rule out an associated carcinoma.
Differential Diagnosis
Similar Entities:
Fibroadenoma with DCIS or LCIS
Phyllodes tumor.
Distinguishing Features:
The distinction between atypia and carcinoma in situ within a fibroadenoma is based on the same criteria used for these lesions in the native breast tissue.
Diagnostic Challenges:
The main challenge is to identify the focal atypia within the fibroadenoma.
Rare Variants:
There are no specific rare variants.
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]