Definition/General

Introduction:
-Glassy cell carcinoma of the breast is an extremely rare and aggressive subtype of adenocarcinoma
-It is characterized by cells with abundant, eosinophilic, ground-glass cytoplasm, distinct cell borders, and large nuclei with prominent nucleoli
-It is more commonly found in the cervix.
Origin:
-The origin is uncertain, but it is considered to be a form of high-grade adenosquamous carcinoma.
Classification: It is a rare variant of invasive breast carcinoma.
Epidemiology:
-Extremely rare, with only a few case reports in the literature
-It tends to affect younger women and has been reported during pregnancy.

Clinical Features

Presentation: Presents as a large, rapidly growing, palpable breast mass.
Symptoms: A painless breast lump is the most common symptom.
Risk Factors: No specific risk factors are known.
Screening:
-Usually presents as a palpable mass
-Mammographic and ultrasound findings are non-specific.

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Gross Description

Appearance:
-A large, firm, gray-white mass with infiltrative borders.
Characteristics: The tumor is typically large and solid.
Size Location: Can occur anywhere in the breast.
Multifocality: Rare.

Microscopic Description

Histological Features:
-The tumor is composed of sheets and nests of large polygonal cells with abundant, finely granular, eosinophilic cytoplasm that has a "glassy" appearance
-The cell borders are well-defined
-A prominent inflammatory infiltrate, rich in eosinophils and plasma cells, is often present in the stroma.
Cellular Characteristics:
-The cells have large, vesicular nuclei with prominent, centrally located, eosinophilic nucleoli
-Mitotic activity is high.
Architectural Patterns: The growth pattern is typically solid and syncytial.
Grading Criteria: This is a high-grade carcinoma by definition.

Immunohistochemistry

Positive Markers:
-The tumor cells are positive for cytokeratins
-They can show focal positivity for squamous markers like p63.
Negative Markers:
-Typically triple-negative (ER, PR, and HER2 negative).
Diagnostic Utility: IHC is used to support the diagnosis and to exclude other tumor types.
Molecular Subtypes: Classified as triple-negative.

Molecular/Genetic

Genetic Mutations: The molecular genetics are not well characterized due to its rarity.
Molecular Markers: No specific molecular markers are routinely used for diagnosis.
Prognostic Significance:
-The prognosis is very poor, with a high rate of local and distant recurrence.
Therapeutic Targets:
-Treatment is primarily surgical
-As a triple-negative cancer, it does not respond to hormonal or HER2-targeted therapy
-Platinum-based chemotherapy is often used.

Differential Diagnosis

Similar Entities:
-High-grade adenocarcinoma NST
-Apocrine carcinoma
-Metaplastic carcinoma.
Distinguishing Features:
-High-grade adenocarcinoma NST lacks the characteristic glassy cytoplasm and prominent inflammatory infiltrate
-Apocrine carcinoma has more granular cytoplasm and is positive for AR and GCDFP-15
-Metaplastic carcinoma may have other mesenchymal components.
Diagnostic Challenges: The main challenge is its rarity and distinguishing it from other high-grade triple-negative breast cancers.
Rare Variants: The entire entity is a rare variant.

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]