Definition/General

Introduction:
-A complex fibroadenoma is a fibroadenoma that contains one or more complex features, including cysts (>3mm), sclerosing adenosis, epithelial calcifications, or papillary apocrine change
-These features distinguish it from a simple fibroadenoma.
Origin: It arises from the terminal duct-lobular unit (TDLU).
Classification: It is a subtype of fibroadenoma.
Epidemiology:
-They are common, and the frequency increases with age.

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 that may have calcifications.

Master Complex Fibroadenoma Pathology with RxDx

Access 100+ pathology videos and expert guidance with the RxDx app

Gross Description

Appearance:
-A well-circumscribed, encapsulated, firm, gray-white mass.
Characteristics: The cut surface is whorled and may have visible cysts.
Size Location: Size is variable.
Multifocality: Can be multiple.

Microscopic Description

Histological Features:
-The lesion is a fibroadenoma with one or more of the following features: cysts (>3mm), sclerosing adenosis, epithelial calcifications, or papillary apocrine change.
Cellular Characteristics: The epithelial and stromal cells are benign.
Architectural Patterns:
-The background is that of a fibroadenoma, with the addition of the complex features.
Grading Criteria: This is a benign lesion.

Immunohistochemistry

Positive Markers: The IHC profile is similar to that of a conventional fibroadenoma.
Negative Markers: Not typically required for diagnosis.
Diagnostic Utility: IHC is not usually necessary for diagnosis.
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: Complex fibroadenomas are associated with a small increased risk (about 2-3 fold) of developing invasive breast cancer.
Therapeutic Targets:
-Treatment is usually conservative (observation)
-Excision may be performed for large or symptomatic lesions.

Differential Diagnosis

Similar Entities:
-Simple fibroadenoma
-Phyllodes tumor.
Distinguishing Features:
-Simple fibroadenomas lack the complex features
-Phyllodes tumors have a more cellular stroma and a leaf-like architecture.
Diagnostic Challenges: The main challenge is to identify the complex features and to distinguish it from a phyllodes tumor.
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]