A minute pigmented skin lesion

Every melanoma begins its life as a minute lesion - smaller than can be seen by the naked eye.

An understanding of embryonic lesions has enabled us to diagnose melanomas at much earlier stages. The

Professor Cliff Rosendahl5th December 2018

In his book Thinking, Fast and Slow, Daniel Kahneman explores the ways we think and identifies two thought processes.

He describes type 1 thinking, by which we do things like recognising faces; and

The presentation of melanoma can break the clinical pattern of other lesions at the same anatomical location by virtue of its size, shape or colour.

However, because the chaotic behaviour of

The growth and morphology of melanoma both reflect the chaotic behaviour of malignant tissue that is disorganised, unrestrained and unpredictable.

Melanomas may break the pattern of surrounding

The majority of melanomas arise without any evidence of a pre-existing naevus.

In cases where melanoma does occur in association with a naevus, there is persisting confusion about whether the

It is known that acquired melanocytic naevi are not expected on the head and neck.1-3

Congenital-type naevi are commonly seen at this location, being raised naevi that often exhibit terminal hairs as

Sponsored This publication is supported by funding from the Australian Government Department of Health. Common Sense Pathology is developed by the Royal College of Pathologists of Australasia and…
15th March 2019

A GP or dermatologist can be highly trained, have the best equipment and consult with patients according to guidelines, but all of that might achieve nothing if the encounter does not uncover a

Lesions which pique interest because of their asymmetry deserve closer scrunity

A dermatoscopist performing a skin check recognises benign lesions in the same way that we recognise people’s faces —

All published algorithms for melanoma rely on asymmetry of pattern and/or colour (chaos) as the fundamental identifier of a suspicious lesion.

Size has also been described as an important feature,

Patients with multiple naevi pose particular challenges but asymmetry aids diagnosis.


Two risk factors give a patient a high risk of melanoma, defined in the Australasian melanoma guidelines as a

Melanoma eventually declares itself clinically as a lesion which “breaks the pattern” by virtue of its location, size, shape, unexpected structure/colour, or all of the above.

This is because of the