Definition/General
Introduction:
Acute mastitis is an acute inflammation of the breast, usually caused by a bacterial infection
It is most common during lactation (lactational mastitis).
Origin:
It is typically caused by bacteria, most commonly Staphylococcus aureus, which enter the breast tissue through cracks in the nipple.
Classification:
It is a benign inflammatory condition
It can be complicated by abscess formation.
Epidemiology:
It is most common in lactating women, affecting up to 10% of breastfeeding mothers.
Clinical Features
Presentation:
Presents with a painful, swollen, red, and warm area of the breast
Systemic symptoms like fever and malaise are common.
Symptoms:
Breast pain, swelling, erythema, and warmth are the key symptoms.
Risk Factors:
Lactation, nipple cracks or fissures, and milk stasis are the main risk factors.
Screening:
The diagnosis is usually clinical
Ultrasound can be used to look for an abscess.
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Gross Description
Appearance:
An ill-defined, indurated, erythematous area
If an abscess has formed, a fluctuant mass with a cavity containing pus will be present.
Characteristics:
The tissue is edematous and congested.
Size Location:
Can affect any part of the breast.
Multifocality:
Usually unifocal.
Microscopic Description
Histological Features:
The key feature is a dense acute inflammatory infiltrate composed predominantly of neutrophils
There is associated edema, vascular congestion, and often, tissue necrosis
In cases of abscess formation, a localized collection of pus is seen.
Cellular Characteristics:
Neutrophils are the dominant cell type.
Architectural Patterns:
A diffuse inflammatory infiltrate is characteristic.
Grading Criteria:
This is a benign inflammatory process.
Immunohistochemistry
Positive Markers:
Immunohistochemistry is not typically required for the diagnosis of acute mastitis.
Negative Markers:
Immunohistochemistry is not typically required for the diagnosis of acute mastitis.
Diagnostic Utility:
IHC is not used for diagnosis
A Gram stain can be used to identify the causative bacteria.
Molecular Subtypes:
Molecular subtyping is not relevant for this benign inflammatory condition.
Molecular/Genetic
Genetic Mutations:
Acute mastitis is an inflammatory condition and is not associated with specific genetic mutations.
Molecular Markers:
No specific molecular markers are routinely used for diagnosis.
Prognostic Significance:
The prognosis is excellent with appropriate antibiotic treatment
If an abscess forms, it may require drainage.
Therapeutic Targets:
Treatment is with antibiotics
Incision and drainage is required for an abscess.
Differential Diagnosis
Similar Entities:
Inflammatory breast carcinoma
Granulomatous mastitis.
Distinguishing Features:
Inflammatory breast carcinoma is a clinical diagnosis, but a biopsy will show dermal lymphatic invasion by carcinoma cells
Granulomatous mastitis has a granulomatous inflammatory infiltrate.
Diagnostic Challenges:
The main challenge is to distinguish acute mastitis from inflammatory breast carcinoma, as the clinical presentation can be similar
A lack of response to antibiotics should raise suspicion for malignancy.
Rare Variants:
There are no specific rare variants of acute mastitis.
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]