Seborrhoeic Keratosis.

A gentle reminder that we are getting older.

What is a Seborrheic Keratosis?

The full word is a mouthful for such a common harmless growth, so let’s shorten it to ‘Seb K.’  Seb K is very common as we get older.

Hearing the name ‘Seb K’ is an expected part of a routine skin check.

Seb K is mainly made up of keratinocytes which are the predominant cells of the upper layer of the skin (epidermis). Keratinocytes produce keratin which is found in scale.

What’s the big deal about Seb Ks? Generally not much except:

  • The lesions may sometimes be itchy.
  • They can also catch on clothing and become inflamed or bleed.
  • You might simply not like them
  • They may appear in large numbers, as is the case when you have an inherited tendency to get them.

The big issue is really that Seb K may occasionally mimic a melanoma.

What does a Seborrheic Keratosis look like?

Seborrhoeic Keratoses have a huge variety of appearances.

I would guess that the a Skin Cancer Doctor is able to confidently ‘name’ a lesion as a ‘Seb K’ around 98% of the time. However, there are many faces of Seb K, and melanoma is forever the concern.

An obvious Seb K is generally scaly and brown in colour (light to dark). The colour varies from pink through to black.

The lesion starts flat, and usually becomes raised from the skin surface – by which time it appears ‘stuck on.’ The surface of The lesion is dull, warty, or waxy.

When you think about it, there are a diverse range of appearances. In my experience, the pink or light brown ones are more likely to be dull, and the darker brown ones are often waxy. You can see this in the gallery.

Dermatoscopy of Seb K will show characteristic features that usually avoids the need for a biopsy – but not always.

A pitfall for the skin cancer doctor is ‘melanoacanthomatous melanoma’ – in other words, a melanoma that looks like a Seb K.