Solar lentigo 

• Clinical features
  • One to multiple brown patches on UV-exposed skin
  • Areas of seborrhoeic keratoses can grow from a solar lentigo
     
• Dermoscopic features include
  • A well-demarcated 'moth-eaten' border
  • Some lesions have multiple lines like a ''fingerprint''

Seborrhoeic keratoses 

• Clinical features of seborrhoeic keratoses (images 1-3)
  • Most are brown or yellow-brown. Occasionally black. Can be skin-coloured
  • May be greasy-looking or scaly with a 'stuck-on' appearance ie the lesion sits on top of normal looking skin and gives the impression that it can be easily picked off. Sometimes segments drop off
  • Although it is common for lesions to grow, they cannot become malignant
  • Easily traumatised - inflammation will settle within 2-3 weeks
     
• Dermoscopic features of seborrhoeic keratoses - there are four main presentations:
   
  • Milia-like cysts and scattered, often irregularly distributed, comedo-like openings (images 4-6). If blood vessels are seen they should be looped, often surrounded by a milky halo, and with a similar appearance throughout (unless traumatised)
     
  • Multiple fissures and ridges, with a 'cerebriform' pattern. Early, flatter lesions can be yellow/brown with a 'coral-fan' like appearance (images 7-12)
     
  • Grouped skin-coloured clods with a central blood vessel - this pattern is mainly seen in pale lesions with a 'frogspawn-like' appearance (images 13-15)
     
  • The clonal variant - small, brown, closely aggregated, monomorphic (of the same or similar appearance) clods - seen in some thinner lesions (images  16-18)

It is worth noting that a non-tender scaly or 'greasy' lesion that dermoscopically is yellow-brown is very likely to be benign.

• Lesions are scaly with filiform projections that may contain black dots (image 19)
   
• Occasionally a wart can coexist with a seborrhoeic keratosis, which is referred to as a verrucous keratosis (images 20,21)

Angioma (images 1-9)

• Clinical features
  • A soft pink/purple papule
  • Can turn black abruptly if become thrombosed
  • Occasionally bleed into the surrounding skin
     
• Dermoscopic features
  • Red-purple (and sometimes black) lacunae, which are usually well-defined and may have white fibrous stroma in-between. Lacunae may turn black if thrombosed
  • Individual blood vessels should not be seen, especially running over the lesion, in such cases melanoma should be suspected

Dermatofibroma (images 1-6)

• Clinical features
  • One-several. Most commonly the limbs, occasionally the trunk. Can be skin-coloured to pink, often with a brown area of peripheral pigmentation
  • Usually a smooth papule or nodule; can be flat or indented (especially on the upper trunk)
  • Pinch positive - place the index finger and thumb a few mm either side of the dermatofibroma, press firmly down and then inwards. With a dermatofibroma (DF) you should be able to palpate a regular rubbery 'button-like' lump, larger than the surface changes. The DF may dimple in the centre
     
• Dermoscopic features
  • Central white structures - can be scar-like; less commonly a white-network or white lines
  • Many lesions have a brown/pink periphery. Variable amounts of a subtle brown rounded network can be seen at the periphery of some lesions

Giant comedones (images 1-6) and cysts (images 7-9)

• Clinical and dermoscopic feautres of giant comedones
  • Several mm to 2 cm in diameter
  • The diagnosis is usually obvious with the comedone clearly visible underneath normal stretched skin - some can be easily expressed by gentle pressure
  • Some lesions are blue - the central keratin differentiates a giant comedone from a blue naevus
     
• Clinical and dermoscopic features of cysts
  • Epidermoid cysts (syn. sebaceous cysts) - smooth regular white/yellow lesions sitting under the skin. As with a comedone a cental punctum may be visible. Dermoscopically elongated vessels can be seen at the periphery resulting from stretching of the skin
  • Pilar cysts - mainly seen on the scalp, lack a central punctum

Lesions with variable amounts of palpable scale or erosions/crust and WITHOUT a palpable lump (papule or nodule) under the scale/crust 

• Actinic keratosis - single to many. Small rough pink macules, often with white surface scale, usually on UV-exposed sites. Non-tender. Refer to the Best Practice Guidelines for management (image 1)
   
• Bowen's disease - single to few. Rough scaly plaque, usually on UV-exposed sites. Non-tender. Refer to the clinical chapter for further reading (image 2)
   
• For other flat scaly lesions refer to the Skin Lesion Diagnostic Tool. Image 3 are stucco keratoses (benign)
   
• Superficial basal cell carcinoma - often presents with one (or more) pink patches, sometimes with scattered crust/erosions as opposed to white-yellow scale. The diagnosis can be confirmed with a punch biopsy (images 4-6)
   
• Cutaneous horn - a cutaneous horn is not a diagnosis, rather it tells us that something is going on in the epidermis. If there is no palpable base/lump under the scale then the lesion is likely to be a viral wart (image 7), or actinic keratosis (image 8). A palpable lump under the horn suggests an SCC (image 9), a diagnosis made more likely if the lesion is tender and growing 

Melanocytic naevi and thin melanoma 

Benign melanocytic naevi (images 1-3) are usually symmetrical, have a regular border, an even colour (or have two-tones of colour that are concentric), and look like the patient's other moles. Soft and wobbly moles are usually benign. A blue naevus is a stable blue (blue/white) macule or papule, often < 5 mm in diameter. There are a wide range of benign pigmented lesions - refer to the Skin Lesion Diagnostic Tool for more detail.  

The following features are suspicious for melanoma-in-situ (including lentigo maligna) and superficial spreading melanoma (images 4-9):

• A= asymmetry of shape or colour - if you draw a line through the middle of the lesion, the two halves don't match
• B = border irregular - the edges of the lesion may be irregular or blurred, and sometimes show notches
• C = colour abnormal - one colour different to the rest of the patient's moles, two colours/shades of colour that are patchy, three colours or shades of colour
• C also stands for comparison ie the ugly duckling that looks different to the patient's other lesions
• D, as first described, stands for diameter > 6mm, however, many skin cancers start small and therefore can present at any size. Thus, D also stands for changing dimensions. It is also important to note:
  • Melanoma grow at different rates - even if the patient states that the lesion is not changing, if it looks suspicious still refer
  • Melanoma often has an irregular appearance, however, if a symmetrical lesion continues to grow out of proportion to the patient's other moles, especially if aged > 45, then melanoma must be considered 

The EFG rule of skin cancer - EFG stands for ALL of Elevated + Firm + Growth persistent > 4 weeks 

Solid BCC (images 1-6) and sebaceous gland hyperplasia (images 7-9)

• Clinical features of a solid BCC - slow growing (2-4 mm per year) with intermittent crusting / bleeding. Firm, non-tender papule / nodule. Shiny / translucent, rolled edge, telangiectasia (more peripheral). With time the nodule becomes more irregular and ulcerates
   
• The dermoscopic appearance of BCC includes any of - gelatinous background, well-focused arborising vessels, central ulceration, well-demarcated blue-grey clods, dot within a clod, MAY globules (multiple white/yellow aggregated clods), shiny white structures (strands or blotches), spoke wheel areas
   
• Most BCC should be referred routinely. Those needing an urgent (or semi-urgent) referral include lesions on/bordering the eyes, nose, mouth and ears, along with large or infiltrative facial lesions 
   
• Sebaceous gland hyperplasia - these are benign, can be solitary but usually multiple, white-yellow facial papules sometimes with an umbilicated centre. Dermoscopically the lesion is comprised of grouped white clods (vessels less well-focused than BCC and should not cross the midline)
   

Squamous cell carcinoma (images 10-11) and keratoacanthoma (image 12)

• Differ from BCC in that they are tender when pressed on, and grow more quickly
• Usually arise on UV-damaged skin
• Well-differentiated SCC are a pink/red papule or nodule with surface scale (or a cutaneous horn) on top
• Moderate to some poorly-differentiated SCC tend to lack scale
• Keratoacanthoma have a similar appearance but tend to grow more quickly and have a symmetrical appearance, an urgent 2WW referral is still needed 
   

Nodular melanoma (images 13-15)

• A firm nodule that can be black, brown, pink, blue, or occasionally skin-coloured, and may bleed
• Metastases and other life-threatening tumours (eg Merkel cell carcinoma) can present in the same way
   

Pyogenic granuloma (images 16-18)

• Are benign, but can have a similar appearance to an amelanotic melanoma (ie a melanoma with no pigment)
   
• Typically, lesions grow quickly, bleed heavily, and may have white emaciated looking skin at their base
   
• Can be managed by advising the patient/carer as follows - apply Vaseline to the surrounding skin, then as much table salt as possible should then be applied to the whole lesion. The Vaseline protects the surrounding skin and helps hold the salt in place over the lesion. Once salt has been applied, it should then be covered (eg using surgical tape or Clingfilm). The process should be repeated every day until the lesion resolves. The patient must be reviewed at two weeks; if the lesion has not resolved the patient needs to be referred urgently to secondary care as a 2WW in case of melanoma

Other lesions of concern requiring an urgent (2WW) referral (images 9-11 are benign)

• Infiltrative BCC (image 1) - usually presents as a firm white/yellow plaque, often affecting the central face
   
• The ''punched-out ulcer'' of a poorly differentiated SCC on UV-damaged skin (image 2) - this differs from a BCC in which an ulcer develops within a papule or nodule
   
• Beware of what looks like granulation tissue, especially without a history of trauma (image 3 is an SCC)
   
• What lies beneath scale/crust - scale/crust should be removed to see what sits underneath. A palpable lesion under crust could represent granulation tissue or an SCC (image 4)
   
• A Marjolin ulcer - an SCC evolving from a leg ulcer or other chronic wound, usually with a heaped edge (image 5)
   
• Subungual melanoma / SCC of the nail can only present in two ways 
   
  • Nail matrix melanoma - any solitary, new or changing line in a nail (any colour), without sparing of the proximal nail (image 6)
     
  • Any destructive process affecting a solitary nail, or persisting area of granulation tissue (image 7 melanoma, image 8 SCC)
     
  • Images 9-10 are all benign as there are none of the features described above
    
     
• Lips
   
  • Regular small brown macules are very likely to be benign mucosal melanocytic macules (image 11) 
     
  • New or changing lesions that are atypical in size, shape or colour should be referred urgently (2WW). Image 12 is melanoma 
     
  • Any solitary erosion/ulcer lasting more than 3 weeks could be an SCC (image 13)
    
     
• Other mucosal surfaces / genitalia
   
  • Have a low threshold for referring pigmented lesions on other mucosal surfaces urgently (2WW) as a good history is hard to obtain (female genital lesions should be referred to gynaecology, oral lesions to orofacial surgery). Image 14 is melanoma
     
  • Pre-malignant lesions and SCC - features can include any of a thickening, lump, or ulcer lasting more than 3 weeks. Image 15 is Bowen's disease, SCC was a differential; an urgent biopsy was needed

If you can't find the lesion on this page:

• Refer to the Skin Lesion Diagnostic Tool