F 34, left leg

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Diagnosis:
Clear cell acanthoma
Comment:

Clinical

Clear cell acanthoma is also known as pale cell acanthoma and Degos’ acanthoma.
It is a rare, slowly growing, sharply demarcated, red or red-brown, dome-shaped papule usually less than 1cm in diameter, occurring mostly on the legs of  adults (>40yrs).

Pathology

Acanthotic epidermis is composed of cells with pale-staining glycogen-rich cytoplasm.
Parakeratosis with neutrophilic keratitis.
Lesional epidermis is sharply demarcated from adjacent normal epidermis.
Neutrophilic infiltration in the pale lesional squamous cells.