Definition/General

Introduction: Phyllodes tumor with inflammatory carcinoma is an exceptionally rare malignant phyllodes tumor where the stromal component contains invasive carcinoma with extensive lymphovascular invasion creating inflammatory breast cancer-like clinical presentation.
Origin:
-Develops from intralobular breast stroma with differentiation toward invasive carcinoma showing extensive lymphovascular involvement
-May arise through aggressive carcinomatous transformation.
Classification:
-WHO Classification categorizes this as malignant phyllodes tumor with heterologous elements
-Inflammatory features defined by extensive dermal lymphatic invasion.
Epidemiology:
-Exceptionally rare with fewer than 5 cases reported worldwide
-Peak age 50-70 years
-Female predominance
-Associated with extremely poor prognosis similar to inflammatory breast cancer.

Clinical Features

Presentation:
-Rapidly enlarging breast with skin changes
-Peau d'orange appearance
-Skin erythema and thickening
-Breast heaviness and tenderness
-Nipple retraction possible.
Symptoms:
-Rapid breast enlargement (weeks to months)
-Skin warmth and erythema
-Breast pain and tenderness
-Peau d'orange skin changes
-Constitutional symptoms possible.
Risk Factors:
-Previous phyllodes tumor history
-Older age
-Aggressive tumor biology
-Rapid growth rate
-Poor prognostic factors.
Screening:
-Clinical presentation often mimics mastitis
-High index of suspicion required
-Imaging shows skin thickening
-Core needle biopsy essential but may be non-diagnostic.

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Gross Description

Appearance:
-Enlarged breast with skin thickening and erythema
-Cut surface shows ill-defined tumor with extensive lymphatic invasion
-Edematous appearance.
Characteristics:
-Often no discrete mass (diffuse involvement)
-Skin thickening prominent
-Lymphatic dilatation visible
-Edematous breast tissue
-Inflammatory appearance.
Size Location:
-Diffuse involvement of breast tissue
-Extensive skin and lymphatic involvement
-Usually involves entire breast quadrant or more
-Bilateral involvement rare.
Multifocality:
-Diffuse multifocal involvement
-Extensive lymphovascular invasion throughout
-Skip lesions common
-Widespread distribution pattern.

Microscopic Description

Histological Features:
-Biphasic tumor with epithelial and mesenchymal components
-Invasive carcinoma with extensive lymphovascular invasion in dermis and breast parenchyma
-Tumor emboli in dilated lymphatics.
Cellular Characteristics:
-Variable cytomorphology depending on carcinoma type
-High nuclear grade typical
-High mitotic activity
-Pleomorphic cells
-Extensive lymphatic involvement.
Architectural Patterns:
-Extensive dermal lymphatic invasion
-Tumor emboli in dilated vessels
-Inflammatory infiltrate
-Stromal edema
-Loss of normal architecture.
Grading Criteria:
-High grade (Grade 3) typical
-High mitotic rate
-Extensive lymphovascular invasion
-Inflammatory changes
-Poor differentiation.

Immunohistochemistry

Positive Markers:
-Cytokeratins positive in tumor emboli
-D2-40 highlights lymphatic invasion
-CD31 shows vascular involvement
-Variable ER/PR/HER2 status
-Epithelial component markers positive.
Negative Markers:
-Variable depending on carcinoma type
-May show triple-negative phenotype
-Lymphoid markers negative in carcinoma cells.
Diagnostic Utility:
-D2-40 essential to demonstrate lymphatic invasion
-Cytokeratins confirm epithelial nature of emboli
-CD31 shows vascular involvement.
Molecular Subtypes:
-Variable molecular subtype
-Often aggressive biology
-May be triple-negative
-HER2-enriched possible.

Molecular/Genetic

Genetic Mutations:
-TP53 mutations common
-PIK3CA mutations
-High tumor mutational burden
-Angiogenesis pathway alterations
-Lymphangiogenesis factors.
Molecular Markers:
-High proliferation markers
-Angiogenesis signatures
-Inflammatory gene expression
-Poor prognostic molecular profile.
Prognostic Significance:
-Extremely poor prognosis
-High metastatic potential
-Resistance to standard therapy
-Similar to inflammatory breast cancer outcomes.
Therapeutic Targets:
-Anti-angiogenic therapy
-Immune checkpoint inhibitors
-Aggressive multimodal therapy
-Novel targeted approaches needed.

Differential Diagnosis

Similar Entities:
-Primary inflammatory breast cancer
-Locally advanced breast cancer with skin involvement
-Infectious mastitis
-Breast lymphoma with skin involvement.
Distinguishing Features:
-Phyllodes with inflammatory: Leaf-like areas, extensive LVI
-Primary IBC: No phyllodes component
-Mastitis: Infectious organisms, no malignancy.
Diagnostic Challenges:
-Clinical distinction from mastitis
-Recognition of phyllodes components
-Assessment of lymphatic invasion
-Tissue sampling challenges.
Rare Variants:
-Inflammatory ductal carcinoma
-Inflammatory lobular carcinoma
-Carcinoma with extensive lymphatic invasion.

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]

Prognostic Factors

Prognostic factors: [list factors]

Final Diagnosis

Final diagnosis: [complete diagnosis]