Papillomas
Intraduct papilloma
Clinical basics
- Often picked up on screening - impalpable
- Symptomatic lesions present as nipple discharge or a lump
- Excision usually recommended after core biopsy diagnosis
Macro view of an excised intraduct papilloma
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Low power view of an intraduct papilloma
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Papillomas - 'must know' histology & FNA basics:
- Distinction from papillary carcinoma can be difficult
- Presence of epithelial and myoepithelial cell layers
- Myoepithelial/basal layer is demonstrated well by immunohistochemistry e.g. with P63 or CK 5/6
- Peripheral scarring and gland entrapment common
- Apocrine metaplasia within lesion common - may be mistaken for invasive behaviour
- FNA:
- FNA appearances can be difficult
- Usually shows a benign pattern but papillary features may not be obvious
- If very cellular may result in a false positive diagnosis of malignancy
- See also papillary carcinoma
Core biopsy of an intraduct papilloma - note the consistent presence of a CK 5/6 positive myoepithelial layer in these sections
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Series of images from a number of intraduct papillomas
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Two small areas from a benign papillary lesion: in the left hand picture it is difficult
to see clearly the myoepithelial cells (arrows); in the right hand picture the
surface epithelium (red arrows) has undergone a mild degree of apocrine metaplasia which
allows it to be distinguished easily from the basal, myoepithelial layer (blue arrows).
A small number of foamy macrophages within the luminal space are present on the extreme left of this picture under the red arrows.
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Florid papillomatosis/Adenoma of the nipple
Clinical basics
- Commonly presents as a symptomatic painless subareolar lump in a 40-50 year old woman
- May also present as nipple/areolar ulceration/erosion + a lump - may therefore be clinically suspicious of Paget's Disease
- May be associated pain, burning, itching
- The history tends to be relatively short
- Imaging may be suspicious of carcinoma
- 5% of cases occur in men and there is a 50% association with co-existent carcinoma in this group
Pathology basics
- Macro
- Usually small (5-10mm) circumscribed white subepidermal nodule
- Micro
- Nodular with or without a central scar with entrapped glands
- Three basic patterns recognised - may be mixed:
- Sclerosing papillomatous
- Papillomatous
- Adenosis type
Pitfalls
- The main risk in these lesions is the misdiagnosis of malignancy:
- Clinically they may be suspicious and the presence of ulceration over the lesion may raise the possibility of Paget's Disease
- An FNA may be misinterpreted
- Because of the sclerosing foci often seen in these lesions a core biopsy could be misinterpreted as showing features of carcinoma - CK5/6 immunostaining will show an intact myoepithelial layer throughout the lesion - see also Immunohistochemistry
Excision biopsy of florid papillomatosis of the nipple - this is predominantly an 'adenosis' pattern.
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Adenomyoepithelioma
Clinical basics
- An uncommon lesion usually presenting as a palpable lump
- Almost always occurring in women - average age 58 years
- Majority are benign but a small proportion have malignant potential - see discussion below
Pathology basics
- Macro
- Usually relatively circumscribed
- Average size 2.5 cm
- May be partly cystic or intracystic - see example below
- Micro
- Most common pattern is a balanced proliferation of glandular (luminal) and myoepithelial elements
- May be focally papillary - hence its inclusion in this section
- Various metaplasias can be seen focally - e.g squamous or apocrine in the luminal component
- Spindle cell metaplasia can be seen in the myoepithelial component
Diagnosis of malignancy
- The guidance on this important point is not clear
- The main problem is the extreme rarity of the lesion which limits the experience of even large centres
- Most authorities raise the possibility of malignant potential if the following features are seen:
- Infiltration of stroma at the periphery of the lesion
- Significant mitotic activity
- Cellular atypia
- Tumour necrosis
- Overgrowth with atypia of either epithelial component is relevant to this assessment
Adenomyoepithelioma - excision biopsy.
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