Definition/General
Introduction:
Papillomatosis, also known as multiple intraductal papillomas, is a benign proliferative breast lesion characterized by the presence of five or more distinct papillomas within a localized segment of the breast.
Origin:
They arise from the ductal epithelium of the terminal duct-lobular units.
Classification:
It is classified as a benign proliferative breast lesion
It is distinguished from a solitary papilloma by its multiplicity.
Epidemiology:
It is less common than solitary papillomas and tends to occur in younger women.
Clinical Features
Presentation:
It is often asymptomatic and found as an incidental finding
It can present with nipple discharge or a palpable mass.
Symptoms:
Nipple discharge is less common than with solitary papillomas.
Risk Factors:
There are no well-established risk factors.
Screening:
Mammography may show a cluster of masses or calcifications.
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Gross Description
Appearance:
Multiple small, friable, polypoid masses within dilated ducts.
Characteristics:
The size of individual papillomas is usually small.
Size Location:
Typically located in the peripheral ducts.
Multifocality:
Defined by its multiplicity.
Microscopic Description
Histological Features:
The lesion consists of multiple intraductal papillomas, each with a fibrovascular core lined by a double layer of epithelial and myoepithelial cells.
Cellular Characteristics:
The cells are bland, without atypia.
Architectural Patterns:
Multiple, distinct papillary lesions are the key feature.
Grading Criteria:
This is a benign lesion
Atypia can be present (atypical papillomatosis).
Immunohistochemistry
Positive Markers:
The myoepithelial cell layer is highlighted by myoepithelial markers such as p63 and calponin.
Negative Markers:
Not typically required for diagnosis.
Diagnostic Utility:
IHC for myoepithelial markers is useful to confirm the benign nature of the lesion.
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:
Papillomatosis is associated with a higher risk of subsequent breast cancer than a solitary papilloma.
Therapeutic Targets:
Surgical excision is often recommended to exclude associated atypia or carcinoma.
Differential Diagnosis
Similar Entities:
Papillary DCIS
Florid usual ductal hyperplasia.
Distinguishing Features:
Papillary DCIS lacks a myoepithelial layer in the papillae
Florid UDH has a different architecture and cytology.
Diagnostic Challenges:
The main challenge is to assess for atypia and to distinguish from papillary DCIS.
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]