Keratoacanthoma

This rapidly engrowing lesion for 2 months was clinically in favor of a keratoacanthoma.


In our case dermoscopy revealed:

• an unspecific pattern
• a central ulceration with blood crusts
• a corona of elongated hairpin blood vessels on a white background corresponding to a white keratotic halo
  

Other dermoscopic features of keratoacanthomas are:

• multicomponent pattern
• polymorphous vessels
• central keratotic plug
  

Elongated hairpin blood vessels on a white keratotic halo are non specific of keratoacanthomas and can be observed in invasive squamous cell carcinomas.

Keratoacanthomas is considered as "benign" variant of squamous cell carcinoma. The first line therapy consists in an excision although other alternatives are possible (imiquimod, PDT, etc...)

Other cases: 1

Squamous cell carcinoma

A 74-year-old man consulted for a scalp tumor.


Dermoscopy revealed an unspecific whitish pattern with a scaly and crusted surface. A biopsy was performed and pathology was in favor of a squamous cell carcinoma (SCC).
Usually, the dermoscopic features of SCC are an unspecific pattern with scales and polymorphous blood vessels typically surrounded by a whitish halo.

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.

Squamous cell carcinoma

A 70-year-old man consulted for a keratotic tumour on his scalp.


Dermoscopy revealed an unspecific pattern, with many polymorphous vessels.
Polymorphous vessels were the only dermoscopic sign in favor of a malignant tumour.
Clinical and dermoscopic features were in favour of squamous cell carcinoma. A biopsy was performed and pathology confirmed this hypothesis.