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Friday, 4 April 2008

Seborrheic keratosis (keratotic subtype)

A 72-year-old man was referred for this scaly lesion on his scalp.

Clinical and dermoscopic evaluation were in favor of a keratotic type of seborrheic keratosis.

Dermoscopy revealed:
  • an unspecific pattern (white to yellow horn masses over a background brown coloration)
  • peripheral hairpin vessels

Seborrheic keratoses in most cases are clinically and dermoscopically diagnosed.

Main dermoscopic signs are:
  • milia-like cysts
  • comedo-like openings (crypts, pseudo follicular openings)
  • fissures and ridges ("brain-like" or cerebration's appearance)
  • fingerprint-like structures
  • moth-eaten border
  • hairpin blood vessels
  • network-like structures
  • sharp demarcation
  • fat fingers
In the keratotic subtype of seborrheic keratosis an unspecific pattern is frequently observed and, because of the exaggerated ortho-hyperkeratosis, local features are not visible.
In our case, dermoscopic examination reveals hairpin blood vessels which is a typical local sign of seborrheic keratosis.