Definition/General
Introduction:
Amyloidosis of the breast is a rare condition characterized by the extracellular deposition of amyloid protein in the breast tissue
It can be a localized process or part of a systemic amyloidosis.
Origin:
Amyloid is a proteinaceous material that is deposited in the extracellular space in various tissues and organs.
Classification:
It can be primary (AL type) or secondary (AA type)
Localized amyloidosis of the breast is usually of the AL type.
Epidemiology:
It is a very rare cause of a breast mass.
Clinical Features
Presentation:
Presents as a firm, palpable mass that can mimic carcinoma.
Symptoms:
A painless breast lump is the most common symptom.
Risk Factors:
Systemic amyloidosis is a risk factor for secondary breast involvement.
Screening:
Mammography can show a mass or microcalcifications.
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Gross Description
Appearance:
A firm, waxy, gray-tan mass.
Characteristics:
The size is variable.
Size Location:
Can occur anywhere in the breast.
Multifocality:
Can be multifocal.
Microscopic Description
Histological Features:
The key feature is the deposition of amorphous, eosinophilic, acellular material (amyloid) in the stroma and around blood vessels and ducts
A foreign body giant cell reaction may be present.
Cellular Characteristics:
A sparse plasma cell infiltrate may be seen, especially in AL amyloidosis.
Architectural Patterns:
The amyloid is deposited in the stroma and vessel walls.
Grading Criteria:
This is a benign process, but it is important to exclude an underlying plasma cell neoplasm.
Immunohistochemistry
Positive Markers:
Amyloid deposits can be typed by IHC for specific amyloid proteins (e.g., kappa and lambda light chains for AL amyloid, serum amyloid A for AA amyloid).
Negative Markers:
Not typically required for diagnosis.
Diagnostic Utility:
IHC is used to type the amyloid
A Congo red stain is the classic special stain for amyloid, which shows apple-green birefringence under polarized light.
Molecular Subtypes:
Molecular subtyping is not relevant for this condition.
Molecular/Genetic
Genetic Mutations:
Amyloidosis is a protein deposition disorder and is not associated with specific genetic mutations in the breast tissue itself.
Molecular Markers:
No specific molecular markers are routinely used for diagnosis.
Prognostic Significance:
The prognosis of localized breast amyloidosis is excellent
The prognosis of systemic amyloidosis depends on the underlying cause and the extent of organ involvement.
Therapeutic Targets:
Treatment of localized amyloidosis is surgical excision
Treatment of systemic amyloidosis is directed at the underlying cause.
Differential Diagnosis
Similar Entities:
Sclerosis
Elastosis
Mucinous carcinoma.
Distinguishing Features:
Sclerosis and elastosis lack the characteristic staining properties of amyloid
Mucinous carcinoma has malignant epithelial cells in pools of mucin.
Diagnostic Challenges:
The main challenge is to consider the diagnosis of amyloidosis and to perform the appropriate special stains (Congo red).
Rare Variants:
There are no specific rare variants of breast amyloidosis.
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]