Definition/General

Introduction:
-Ductal carcinoma in situ (DCIS) arising within a fibroadenoma is a rare event
-The DCIS is confined to the epithelial component of the fibroadenoma.
Origin: The DCIS arises from the epithelial component of the fibroadenoma.
Classification: The DCIS is classified and graded 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 DCIS
-The DCIS can be of any architectural pattern (e.g., cribriform, solid, papillary) and nuclear grade.
Cellular Characteristics: The cytological features are those of DCIS.
Architectural Patterns: The background is that of a fibroadenoma.
Grading Criteria:
-The DCIS is graded as low, intermediate, or high grade.

Immunohistochemistry

Positive Markers: The IHC profile is that of the DCIS.
Negative Markers: Not typically required for diagnosis.
Diagnostic Utility:
-IHC is used to classify the DCIS and to determine ER, PR, and HER2 status.
Molecular Subtypes: The molecular subtype is that of the DCIS.

Molecular/Genetic

Genetic Mutations: The genetic alterations are those of DCIS.
Molecular Markers: No specific molecular markers are routinely used for diagnosis.
Prognostic Significance:
-DCIS arising in a fibroadenoma has an excellent prognosis
-The risk of subsequent invasive cancer is similar to that of DCIS arising in the native breast.
Therapeutic Targets: Treatment is based on the characteristics of the DCIS and follows standard guidelines.

Differential Diagnosis

Similar Entities:
-Fibroadenoma with ADH
-Fibroadenoma with LCIS.
Distinguishing Features:
-The distinction between ADH and low-grade DCIS is based on size
-LCIS is E-cadherin negative.
Diagnostic Challenges: The main challenge is to identify the DCIS 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]