Three-point checklist

Created 2008.

Learning objectives

• Describe and use the 3-point checklist for evaluating pigmented skin lesions by dermoscopy

Introduction

The dermoscopy 3-point checklist for early detection of skin cancer is fairly easy to learn and has a high sensitivity for melanoma. (1) There a high likelihood of malignancy (melanoma or basal cell carcinoma) if a pigmented skin lesion has any two of these criteria. The 3-point checklist has been designed to allow non-experts not to miss detection of melanomas. However, it is not as specific as pattern analysis (described in a later section).

• Asymmetry: asymmetry of colour and structure in one or two perpendicular axes
• Atypical network: pigment network with irregular holes and thick lines
• Blue-white structures: any type of blue and/or white colour, i.e. combination of blue-white veil and regression structures

The main aim of the 3-point checklist is to determine whether the lesion being examined should undergo a biopsy. It does not an require accurate diagnosis to be made as the finer features of the lesion are not examined.

Score = 0 

Score = 1 

Score = 2 

Score = 3 

Symmetry

The following lesions demonstrate approximate symmetry of colour and structure. Shape is not considered.

Cherry angioma 

Compound naevus 

Compound naevus 

Cellular naevus 

Solar lentigo 

Plantar naevus 

Benign naevus 

Seborrhoeic keratosis 

The lesions below demonstrate asymmetry of colour or structure in one or two axes. Not all asymmetrical lesions are malignant.

Melanoma in situ 

Melanoma in situ 

Invasive melanoma 

Basal cell carcinoma 

Plantar naevus 

Seborrhoeic keratosis 

Lentigo simplex 

Congenital naevus 

Network

The following lesions are considered to have typical pigment network.

Junctional naevus 

Ephilis 

Benign naevus 

Junctional naevus 

Ink spot naevus 

Plantar naevus 

Facial lentigo 

Dermatofibroma 

The lesions below have atypical pigment network, with irregular holes and thick lines (broadened network). Streaming or pseudopods would also be considered atypical. Not all lesions with atypical network prove to be malignant.

Irregular pigment network: black arrows to broadened network, asterisk to streaming

Melanoma 

Lentigo maligna 

Melanoma in situ 

Lentigo maligna 

Melanoma 

Lentigo maligna 

Lentigo maligna 

Atypical naevus 

Blue-white structures

Blue-white structures can refer to any type of blue and/or white colour, i.e. combination of blue-white veil and regression structures, as shown in the following pictures. The colour can be subtle. Not all lesions with blue-white structures are malignant.

Melanoma 

Basal cell carcinoma 

Melanoma 

Lentigo maligna 

Congenital naevus 

Blue naevus 

Dysplastic naevus 

Dysplastic naevus 

Activity

Practice dermoscopy, evaluating skin lesions using the 3-point checklist.