Clear cell acanthoma

What is clear cell acanthoma?

Clear cell acanthoma is a rare benign (non-cancerous) epithelial skin tumour. It is usually a solitary lesion appearing on the lower legs but there have been cases of multiple lesions occurring.

Clear cell acanthoma is also known as Degos acanthoma or acanthome à cellules claires.

Clinical features of the lesion include:

• Slightly elevated to dome-shaped plaque or nodule
• Colour varies from pink to brown but is most commonly blood red and shiny
• Can be from 3 to 20 mm in diameter
• The wafer-like crusty scale may be stuck round the edges of the lesion. A moist or bleeding surface may result if the scale is removed.

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* Images provided by Dr Jeremy Hay

How do you get clear cell acanthoma and who is at risk?

It is currently not known why clear cell acanthoma occurs. Although rare, they occur mostly in adults of middle-age or older. Both male and females can be affected.

How is the diagnosis made?

The diagnosis is rarely made before a skin biopsy. However, dermatoscopy is characteristic, as the blood vessels are lined up in strings (see images above). When examined under the microscope, clear cell acanthoma shows a characteristic accumulation of clear glycogen-containing cells in the epidermis.

What treatments are available?

They may persist for years and years without changing or causing any complications. They are easily excised.