Definition/General
Introduction:
Phyllodes tumor with lymphoma is an exceptionally rare collision tumor where a malignant phyllodes tumor contains areas of lymphomatous infiltration
This may represent secondary lymphoma development within phyllodes tumor or collision of two separate neoplasms.
Origin:
May arise through several mechanisms: secondary lymphoma development in phyllodes tumor stroma, collision of two independent tumors, or lymphomatous transformation of stromal cells.
Classification:
WHO Classification categorizes this as composite tumor
Lymphoma component most commonly represents diffuse large B-cell lymphoma or other non-Hodgkin lymphomas.
Epidemiology:
Exceptionally rare with fewer than 20 cases reported in medical literature
Peak age 40-70 years
Female predominance
Associated with aggressive clinical behavior.
Clinical Features
Presentation:
Large, rapidly growing breast mass
May be associated with B-symptoms (fever, night sweats, weight loss)
Lymphadenopathy possible.
Symptoms:
Progressive breast enlargement
Constitutional symptoms possible
Breast pain and tenderness
Skin changes in advanced cases.
Risk Factors:
Previous phyllodes tumor history
Immunocompromised state
Previous radiation exposure
History of lymphoproliferative disorders
Advanced age.
Screening:
No specific screening available
Clinical examination for masses and lymphadenopathy
Imaging with CT/PET for staging if lymphoma suspected.
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Gross Description
Appearance:
Large, multinodular mass with variable consistency
Cut surface shows gray-white to tan areas
Possible fleshy, fish-flesh appearance in lymphomatous areas.
Characteristics:
Size typically >5 cm (range 3-15 cm)
Firm to soft consistency
Irregular borders
Areas of necrosis possible
Hemorrhage variable.
Size Location:
Can occur in any breast region
Usually involves significant breast volume
Unilateral presentation typical
May extend beyond breast.
Multifocality:
Typically unifocal large mass
Lymphomatous areas may be multifocal within tumor
Extranodal extension possible.
Microscopic Description
Histological Features:
Biphasic tumor with epithelial component and mesenchymal stroma
Areas of dense lymphoid infiltration replacing normal stroma
Monotonous lymphoid cells with high mitotic activity.
Cellular Characteristics:
Large atypical lymphoid cells with vesicular nuclei
Prominent nucleoli
High nuclear-cytoplasmic ratio
Frequent mitoses and apoptotic bodies.
Architectural Patterns:
Sheets of lymphoid cells
Diffuse growth pattern typical
Starry-sky appearance possible
Residual phyllodes architecture focally preserved.
Grading Criteria:
High-grade malignant phyllodes tumor
Lymphoma component shows high-grade cytologic features
Numerous mitoses
Extensive necrosis possible.
Immunohistochemistry
Positive Markers:
Lymphoma cells: CD20+ (B-cell), CD3+ (T-cell), Ki-67 high
LCA/CD45 positive
Epithelial component: CK7+, EMA+.
Negative Markers:
Lymphoma cells: Cytokeratins negative, S-100 negative
CD30 variable
Epithelial component: LCA negative.
Diagnostic Utility:
CD20 confirms B-cell lymphoma
CD3 for T-cell lymphoma
Ki-67 shows high proliferation rate
Flow cytometry helpful for clonality.
Molecular Subtypes:
Diffuse large B-cell lymphoma (most common)
Primary mediastinal B-cell lymphoma
T-cell lymphoma (rare)
Burkitt lymphoma (rare).
Molecular/Genetic
Genetic Mutations:
MYC rearrangements (if Burkitt-like)
BCL2 rearrangements
BCL6 rearrangements
TP53 mutations
Complex karyotype possible.
Molecular Markers:
Clonal immunoglobulin rearrangements (B-cell)
T-cell receptor rearrangements (T-cell)
High proliferation index
EBV association possible.
Prognostic Significance:
Double-hit lymphoma (MYC + BCL2/BCL6) has poor prognosis
High Ki-67 (>90%) adverse factor
Stage and bulk important.
Therapeutic Targets:
CD20-targeted therapy (rituximab) for B-cell lymphoma
BTK inhibitors
BCL2 inhibitors
CAR-T therapy in relapsed cases.
Differential Diagnosis
Similar Entities:
Primary breast lymphoma
Metastatic lymphoma to breast
Inflammatory breast carcinoma
Anaplastic large cell lymphoma
Lymphomatoid granulomatosis.
Distinguishing Features:
Phyllodes with lymphoma: Leaf-like areas, CD20+
Primary lymphoma: No phyllodes component
Inflammatory carcinoma: Cytokeratin positive.
Diagnostic Challenges:
Recognition of lymphomatous areas
Flow cytometry essential
Distinction from inflammatory infiltrate
Assessment of clonality.
Rare Variants:
Hodgkin lymphoma component
NK/T-cell lymphoma
Plasmablastic lymphoma
MALT lymphoma (rare).
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]