Definition/General
                                                                                Introduction: 
                                                                                A fibroadenoma with usual ductal hyperplasia (UDH) is a fibroadenoma that contains foci of UDH within its epithelial component.                                    
                                
                                                                                Origin: 
                                                                                The UDH arises from the epithelial component of the fibroadenoma.                                    
                                
                                                                                Classification: 
                                                                                It is a subtype of complex fibroadenoma.                                    
                                
                                                                                Epidemiology: 
                                                                                UDH is a common finding in fibroadenomas.                                    
                                Clinical Features
                                                                                        Presentation: 
                                                                                        Presents as a painless, firm, mobile, well-circumscribed, rubbery mass, similar to a simple fibroadenoma.                                        
                                    
                                                                                        Symptoms: 
                                                                                        A painless, mobile lump is the most common symptom.                                        
                                    
                                                                                        Risk Factors: 
                                                                                        There are no well-established risk factors.                                        
                                    
                                                                                        Screening: 
                                                                                        On mammography, they appear as a well-circumscribed, oval mass.                                        
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Gross Description
                                                                                        Appearance: 
                                                                                                                                
                                    A well-circumscribed, encapsulated, firm, gray-white mass.
                                                                                        Characteristics: 
                                                                                        The gross appearance is indistinguishable from a simple fibroadenoma.                                        
                                    
                                                                                        Size Location: 
                                                                                        Size is variable.                                        
                                    
                                                                                        Multifocality: 
                                                                                        Can be multiple.                                        
                                    Microscopic Description
                                                                                        Histological Features: 
                                                                                                                                
                                    The lesion is a fibroadenoma with a focus of UDH
The UDH is characterized by a proliferation of a mixed population of epithelial and myoepithelial cells, with irregular, slit-like secondary lumens.
                                                                                        Cellular Characteristics: 
                                                                                        The cytological features are those of UDH.                                        
                                    
                                                                                        Architectural Patterns: 
                                                                                        The background is that of a fibroadenoma.                                        
                                    
                                                                                        Grading Criteria: 
                                                                                        This is a benign lesion.                                        
                                    Immunohistochemistry
                                                                                        Positive Markers: 
                                                                                        The UDH component shows a mosaic pattern of staining for CK5/6.                                        
                                    
                                                                                        Negative Markers: 
                                                                                        Not typically required for diagnosis.                                        
                                    
                                                                                        Diagnostic Utility: 
                                                                                        IHC for CK5/6 can be used to confirm the UDH component.                                        
                                    
                                                                                        Molecular Subtypes: 
                                                                                        Molecular subtyping is not relevant for this benign condition.                                        
                                    Molecular/Genetic
                                                                                        Genetic Mutations: 
                                                                                        Not well characterized.                                        
                                    
                                                                                        Molecular Markers: 
                                                                                        No specific molecular markers are routinely used for diagnosis.                                        
                                    
                                                                                        Prognostic Significance: 
                                                                                                                                
                                    A fibroadenoma with UDH is associated with a small increased risk of subsequent breast cancer, similar to that of UDH in the absence of a fibroadenoma.
                                                                                        Therapeutic Targets: 
                                                                                        No specific treatment is required.                                        
                                    Differential Diagnosis
                                                                                Similar Entities: 
                                                                                Fibroadenoma with ADH.                                    
                                
                                                                                Distinguishing Features: 
                                                                                ADH has a monotonous cell population and is negative for CK5/6.                                    
                                
                                                                                Diagnostic Challenges: 
                                                                                The main challenge is to distinguish UDH from ADH within a fibroadenoma.                                    
                                
                                                                                Rare Variants: 
                                                                                There are no specific rare variants.                                    
                                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]