Definition/General

Introduction: Phyllodes tumor with cribriform carcinoma is an extremely rare malignant phyllodes tumor where the stromal component contains cribriform carcinoma characterized by sieve-like glandular structures with punched-out spaces.
Origin:
-Develops from intralobular breast stroma with differentiation toward cribriform carcinoma
-May arise through specific glandular differentiation of stromal cells forming characteristic cribriform architecture.
Classification:
-WHO Classification categorizes this as malignant phyllodes tumor with heterologous elements
-Cribriform carcinoma component shows characteristic sieve-like architecture.
Epidemiology:
-Exceptionally rare with fewer than 5 cases reported worldwide
-Peak age 45-65 years
-Female predominance
-Clinical behavior depends on grade and extent of cribriform component.

Clinical Features

Presentation:
-Large, slowly to moderately growing breast mass
-Usually presents as painless mass
-May show gradual enlargement over months.
Symptoms:
-Progressive breast enlargement
-Breast asymmetry
-Usually asymptomatic initially
-May become symptomatic with large size
-Nipple discharge rare.
Risk Factors:
-Previous phyllodes tumor history
-Middle to older age
-Family history of breast cancer
-Possible hormonal factors.
Screening:
-No specific screening available
-Clinical examination for masses
-Imaging with mammography and ultrasound
-Core needle biopsy for diagnosis.

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Gross Description

Appearance:
-Large, well-circumscribed to partially circumscribed mass
-Cut surface shows gray-white areas with possible cystic spaces
-Firm consistency.
Characteristics:
-Size typically >4 cm (range 3-12 cm)
-Firm consistency
-May have characteristic honeycomb or sieve-like areas
-Small cystic spaces possible.
Size Location:
-Can occur in any breast region
-Usually involves moderate to significant breast tissue
-Unilateral presentation typical.
Multifocality:
-Typically unifocal mass
-Multifocal cribriform areas within tumor
-Complex glandular architecture
-Local extension uncommon.

Microscopic Description

Histological Features:
-Biphasic tumor with epithelial and mesenchymal components
-Cribriform carcinoma areas show characteristic sieve-like glandular structures with round, punched-out spaces.
Cellular Characteristics:
-Cuboidal to low columnar epithelial cells lining cribriform spaces
-Uniform nuclear features
-Low to moderate mitotic activity
-Minimal nuclear pleomorphism.
Architectural Patterns:
-Sieve-like or honeycomb architecture
-Round, punched-out spaces of varying sizes
-Back-to-back glandular structures
-Minimal intervening stroma.
Grading Criteria:
-Usually low to intermediate grade
-Uniform nuclear features
-Low mitotic rate
-Well-organized cribriform architecture indicates lower grade.

Immunohistochemistry

Positive Markers:
-Cytokeratins positive (CK7 strong, CK20 negative)
-EMA positive
-Estrogen receptor often positive
-Progesterone receptor often positive
-Epithelial component: CK7+, EMA+.
Negative Markers:
-TTF-1 negative
-CDX2 negative
-p63 negative
-CK5/6 negative
-Myoepithelial markers negative.
Diagnostic Utility:
-Hormone receptor positivity common
-Absence of myoepithelial markers confirms invasive carcinoma
-CK7 positive, CK20 negative pattern typical.
Molecular Subtypes:
-Hormone receptor-positive type
-Low-grade cribriform carcinoma
-High-grade cribriform carcinoma (rare).

Molecular/Genetic

Genetic Mutations:
-PIK3CA mutations common
-ESR1 mutations possible
-TP53 mutations rare in low-grade tumors
-Low tumor mutational burden.
Molecular Markers:
-Luminal-type gene expression profile
-High estrogen receptor expression
-Low Ki-67 proliferation index
-GATA3 expression positive.
Prognostic Significance:
-Hormone receptor status predicts response to therapy
-Low grade associated with better prognosis
-PIK3CA mutations may affect targeted therapy.
Therapeutic Targets:
-Endocrine therapy (tamoxifen, aromatase inhibitors)
-CDK4/6 inhibitors
-PI3K pathway inhibitors for PIK3CA-mutated tumors.

Differential Diagnosis

Similar Entities:
-Invasive cribriform carcinoma of breast
-Adenoid cystic carcinoma
-Ductal carcinoma in situ with cribriform pattern
-Atypical ductal hyperplasia.
Distinguishing Features:
-Phyllodes with cribriform: Leaf-like areas, stromal overgrowth
-Adenoid cystic: Myoepithelial cells, specific markers
-DCIS: In situ, myoepithelial layer.
Diagnostic Challenges:
-Recognition of cribriform features
-Distinction from adenoid cystic carcinoma
-Assessment of invasion vs in situ
-Phyllodes component identification.
Rare Variants:
-Cribriform carcinoma with micropapillary features
-Mixed cribriform and tubular carcinoma
-Cribriform with neuroendocrine differentiation.

Sample Pathology Report

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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]