Home Teledermatology for suspected skin cancers Clinical features of skin lesions CME
Teledermatology for suspected skin cancers
Created 2017.
Skin cancers and precursor lesions should be identified and removed.
- Melanoma and melanoma in situ
- Squamous cell carcinoma, intraepidermal carcinoma and actinic keratoses (where practical)
- Basal cell carcinoma
Benign skin lesions should be identified. They don’t need removal, unless:
- They appear suspicious for skin cancer
- They are causing symptoms
- The patient requests removal and accepts the consequences (eg scar)
General characteristics of skin cancer are:
- Enlarging or changing over time (weeks to years)
- Irregular in shape, surface, colour, structure
- May bleed or ulcerate without injury
General characteristics of benign skin lesions are:
- Stable
- Uniform in surface, colour, structure
- Often symmetrical in shape
- Any bleeding or ulceration is due to recent injury
Melanoma
- ABCDE characteristics
- Asymmetry, Border irregularity, Colour variation, Diameter >6mm (or Different), Evolving
- Typical of superficial forms of melanoma
- Not always present, especially in nodular melanoma
- Glasgow 7-point checklist
Major features:
- Change in size
- Irregular shape
- Irregular colour
Minor features:
- Diameter >7mm
- Inflammation
- Oozing
- Change in sensation
- Useful for invasive melanoma
- May miss in-situ melanoma
- A changing/enlarging lesion
- This may or may not be observed
- Benign lesions can change
- Asymmetrical/irregular/variable colour, structure, surface
- Shape is often irregular
- Sometimes, melanoma is round
- Size is often > 6 mm
- Melanoma can be diagnosed when much smaller
- Even experts miss some cases of melanoma
- They can look similar to other lesions, especially seborrhoeic keratoses, solar lentigines and benign naevi
- Be vigilant!
When evaluating pigmented lesions, especially if of concern to the patient, explain that diagnosis can be difficult:
- Early melanoma often looks the same as a mole or freckle.
- Most lesions that concern patients are entirely harmless.
- Self skin examination is useful.
- Any changing lesion, including any evaluated on this occasion, is worth showing to your doctor.
- If the patient is concerned for any reason, return for re-evaluation.
- A second opinion can be obtained using Teledermatoscopy.
- The lesion could be excised for pathological examination.
Most melanomas arise from normal skin. Precursor lesions include:
- Melanocytic naevus: any kind.
- Giant congenital melanocytic naevi > 40 cm diameter.
- Atypical lentiginous hyperplasia and atypical junctional naevus of the elderly. These are irregular pigmented patches in sun damaged skin of face, neck, upper trunk but clinical/dermatoscopic/histopathological characteristics do not meet criteria for diagnosis of melanoma.
If the lesion is likely benign, explain reasons against unnecessary excision:
- Unnecessary expense.
- Unnecessary scar.
- Unnecessary risk of complications eg infection, haemorrhage, delayed wound healing, drug allergy.
- Pathological diagnosis can also be uncertain or incorrect.
- Patient has other similar lesions that are not concerning to the patient or to their doctor.
Also explain the reasons that partial biopsy is generally avoided.
- Melanoma can be focal within a skin lesion and partial biopsy may miss it.
- Pathological diagnosis is very difficult and the pathologist needs a large sample to be confident.
- Biopsy result can be misleading.
Invasive squamous cell carcinoma
- Grows over weeks to months.
- Tender, painful plaque or nodule.
- It has a dermal component. Palpation often detects a rubbery component within the skin.
- Well-differentiated SCC is scaly, warty.
- Undifferentiated or anaplastic SCC may be difficult to distinguish from other epithelial cancers or even from melanoma histologically.
- These lesions often present as nonspecific enlarging ulcers or ulcerated irregular plaques.
Precursor lesions are actinic keratoses and intraepidermal carcinoma for SCC.
Basal cell carcinoma
- Grows over months to decades
- Early bleeding and ulceration
- Pearly nodule, plaque or edge
- May be skin coloured or pink
- Superficial BCC is an irregular plaque with small erosions and light scale
There is no precursor lesion for BCC.
Related information
On DermNet NZ
- Skin lesions, tumours and cancers
- Invasive melanoma
- Lentigo maligna / Lentigomaligna melanoma
- Lentiginous melanoma
- Superficial spreading melanoma
- Nodular melanoma
- Acral lentiginous melanoma
- Congenital naevus
- Atypical naevus
- Actinic keratosis/es
- Squamous cell carcinoma / SCC
- Keratoacanthoma
- Intraepidermal carcinoma / IEC / squamous cell carcinoma in situ (formerly Bowen disease)
- Basal cell carcinoma / BCC
- Seborrhoeic keratosis
- Lentigines
- Ephelis/ephelides
- Sebaceous hyperplasia
- Dermatofibroma
- Neurofibroma
- Cysts
- Corn and callus
- Viral warts
- Vascular proliferations and abnormalities of blood vessels
- Common skin lesions CME course
Other websites and resources
Text: Miiskin