Pilar Sheath Acanthoma

Pilar Sheath AcanthomaScanning magnification of a pilar sheath acanthoma shows a dilated follicular structure lined by a thickened squamous epithelium with endophytic, lobulated areas image.

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Pilar Sheath Acanthoma at Higher MagnificationHigher magnification of the lobular areas shows acanthotic squamous epithelium with peripheral palisading image and scattered clear-staining cells image.
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Pilar Sheath Acanthoma With Prominent Granular LayerHigh magnification of the epithelium shows a prominent granular layer image (consistent with infundibular keratinization). The cells are mildly enlarged and squamoid appearing, with scattered pale/clear cells image.
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Pilar Sheath Acanthoma With Squamous PearlsFoci of keratinization with squamous pearls image may be seen surrounded by bland squamoid to clear image cells.

TERMINOLOGY

Abbreviations

• Pilar sheath acanthoma (PSA)

Definitions

• Mature adnexal proliferation composed of thickened epithelium with enlarged pale-staining keratinocytes

ETIOLOGY/PATHOGENESIS

Unknown

• No known causes/associations

CLINICAL ISSUES

Epidemiology

• Incidence
image Rare lesions
• Age
image Usually occur in middle-aged to older adults
• Sex
image Males and females equally affected

Site

• Most often occur on upper lip

Presentation

• Keratotic papular lesion with central pore-like area

Natural History

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Apr 24, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Pilar Sheath Acanthoma

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