Definition/General
Introduction:
Lobular carcinoma in situ (LCIS) arising within a fibroadenoma is the most common type of carcinoma to be found in a fibroadenoma
The LCIS is confined to the epithelial component of the fibroadenoma.
Origin:
The LCIS arises from the epithelial component of the fibroadenoma.
Classification:
The LCIS is classified according to the standard criteria.
Epidemiology:
It is most common in perimenopausal and postmenopausal women.
Clinical Features
Presentation:
Presents as a palpable breast mass, often with a recent history of growth.
Symptoms:
A breast lump is the most common symptom.
Risk Factors:
The risk factors are those for breast cancer in general.
Screening:
Mammography may show a well-circumscribed mass with suspicious features, such as indistinct margins or calcifications.
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Gross Description
Appearance:
The gross appearance is usually that of a fibroadenoma.
Characteristics:
Gross findings are not specific for this microscopic diagnosis.
Size Location:
Gross findings are not specific for this microscopic diagnosis.
Multifocality:
Gross findings are not specific for this microscopic diagnosis.
Microscopic Description
Histological Features:
The lesion is a fibroadenoma with a focus of LCIS
The LCIS is characterized by a proliferation of small, discohesive cells that fill and expand the ductules within the fibroadenoma.
Cellular Characteristics:
The cytological features are those of LCIS.
Architectural Patterns:
The background is that of a fibroadenoma.
Grading Criteria:
LCIS is a low-grade lesion.
Immunohistochemistry
Positive Markers:
The LCIS cells are ER and PR positive.
Negative Markers:
The key finding is the loss of E-cadherin expression in the LCIS cells.
Diagnostic Utility:
IHC for E-cadherin is essential to confirm the lobular nature of the in situ carcinoma.
Molecular Subtypes:
Molecular subtyping is not relevant for this pre-invasive lesion.
Molecular/Genetic
Genetic Mutations:
Loss of the CDH1 gene is the key genetic event.
Molecular Markers:
No specific molecular markers are routinely used for diagnosis.
Prognostic Significance:
LCIS arising in a fibroadenoma is a risk factor for subsequent invasive carcinoma in both breasts
The management is similar to that of LCIS found in the native breast.
Therapeutic Targets:
Treatment is usually conservative, with follow-up
Risk-reducing medication may be considered.
Differential Diagnosis
Similar Entities:
Fibroadenoma with ALH
Fibroadenoma with DCIS.
Distinguishing Features:
The distinction between ALH and LCIS is quantitative
DCIS is E-cadherin positive.
Diagnostic Challenges:
The main challenge is to identify the LCIS 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]