43. Seborrhoeic keratosis: Difference between revisions

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[[File:Seborrheic keratosis - overview.png|thumb|Overview. Hyperkeratosis is visible.|354x354px]]'''Staining''': HE
[[File:Seborrheic keratosis - overview.png|thumb|Overview. Hyperkeratosis is visible.|300x300px]]'''Staining''': HE


'''Organ''': Skin
'''Organ''': Skin
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A well-circumscribed skin lesion is visible.
A well-circumscribed skin lesion is visible.


The stratum corneum is thickened, meaning that there is ''hyperkeratosis''. The cells of the stratum corneum have retained their nuclei, meaning that there is ''parakeratosis''.
The stratum corneum is thickened, meaning that there is ''hyperkeratosis''. The cells of the stratum corneum have retained their nuclei, meaning that there is ''parakeratosis''.[[File:Seborrheic keratosis - neutrophils.png|thumb|These are neutrophils and not neutrophilic microabscesses (as in psoriasis)|333x333px]]


There are neutrophils in the stratum corneum. These are not related to the disease and are instead the result of the patient scratching the seborrheic keratosis, causing irritation.[[File:Seborrheic keratosis - neutrophils.png|thumb|These are neutrophils and not neutrophilic microabscesses (as in psoriasis)|333x333px]]The basal layer of the epidermis contains keratin cysts, called ''horn cysts''. These are formed as the stratum corneum invaginates into the cellular layer of the epidermis, which is also visible on the slide.
There are neutrophils in the stratum corneum. These are not related to the disease and are instead the result of the patient scratching the seborrheic keratosis, causing irritation.


There is acanthosis, which is visible as the presence of dermal cells in small nests inside the epidermis.
The basal layer of the epidermis contains keratin cysts, called ''horn cysts''. These are formed as the stratum corneum invaginates into the cellular layer of the epidermis, which is also visible on the slide.


'''Diagnosis''': Seborrheic keratosis
There is acanthosis, which is visible as the presence of dermal cells in small nests inside the epidermis.[[File:Seborrheic keratosis - horn cysts.png|thumb|Acanthosis, the disruption of the epidermis, is also visible. Large melanin pigments are also visible, which give the seborrheic keratoses their black colour|313x313px]]'''Diagnosis''': Seborrheic keratosis


'''Causes''':
'''Causes''':
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* Unknown
* Unknown
* Paraneoplastic (Leser-Trelat sign)
* Paraneoplastic (Leser-Trelat sign)
[[File:Seborrheic keratosis - horn cysts.png|thumb|Acanthosis, the disruption of the epidermis, is also visible. Large melanin pigments are also visible, which give the seborrheic keratoses their black colour|313x313px]]'''Theory''':
'''Theory''':


Sporadic seborrheic keratoses usually appear in elderly persons. If dozens of keratoses appear within a short period of time, it is a paraneoplastic syndrome called Leser-Trelat sign. This suggests an internal cancer, most commonly a <abbr>GI</abbr> tract carcinoma.
Sporadic seborrheic keratoses usually appear in elderly persons. If dozens of keratoses appear within a short period of time, it is a paraneoplastic syndrome called Leser-Trelat sign. This suggests an internal cancer, most commonly a <abbr>GI</abbr> tract carcinoma.
[[Category:Pathology 2 - Histopathology slides]]
[[Category:Pathology 2 - Histopathology slides]]