FFinalistSouthampton · 2027
Dermatology
AKT · Dermatology/Malignant & pre-malignant

Malignant melanoma

Malignancy of melanocytes (UV, naevi, genetic)

Overview

A malignancy of melanocytes with the potential for early metastasis — the skin cancer that kills. Recognised by the ABCDE rule and the "ugly duckling" sign. Prognosis is driven by BRESLOW THICKNESS (depth of invasion), which is why early excision matters so much.

Recognise

  • ABCDE: Asymmetry, Border irregularity, Colour variation, Diameter >6 mm, Evolution (change) — and the "ugly duckling" lesion that stands out from the rest
  • Subtypes: superficial spreading (commonest), nodular (rapid vertical growth, worst prognosis), lentigo maligna (sun-damaged face of the elderly), acral lentiginous (palms/soles/nails — Hutchinson sign on the nail fold)
  • New or changing pigmented lesion; bleeding/itch are later features

Red flags

  • Any new/changing/bleeding pigmented lesion, a positive ABCDE or ugly-duckling sign, or a pigmented nail streak with Hutchinson sign → 2-week-wait referral

Differentials & how to tell them apart

Benign melanocytic naevussymmetrical, uniform colour, stable — melanoma is asymmetric, irregular and changing
Seborrhoeic keratosis"stuck-on" warty plaque with horn cysts, well-defined, benign
Pigmented BCCpearly with telangiectasia — biopsy if uncertain
Subungual haematomaa nail bruise GROWS OUT with the nail and has no Hutchinson sign, unlike subungual melanoma

Clinical image

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Malignant melanoma — clinical imagesDermNet

Investigations

Dermoscopy then EXCISION biopsy (never partial/shave) of the whole lesion for histology and Breslow thickness. 2-week-wait referral. Sentinel-node biopsy and staging for thicker lesions; never just monitor a suspicious lesion.

Management

Urgent excision biopsy of the whole lesion → wide local excision by Breslow thickness

  1. 1Refer on the 2-week-wait pathway. Perform an EXCISION biopsy of the entire lesion (not a partial/shave biopsy) to obtain Breslow thickness, then wide local excision with margins guided by thickness.Gate: Never partial-biopsy or "watch" a suspicious pigmented lesion — excise it whole, because BRESLOW THICKNESS determines staging, margins and prognosis and is lost with an incomplete sample
  2. 2Sentinel-node biopsy + staging for intermediate/thick lesions; metastatic disease → immunotherapy or BRAF/MEK-targeted therapy via the oncology MDT.
Wide local excision — definitive treatment; margins set by Breslow thickness
Sentinel lymph node biopsy — staging for intermediate/thick melanomas
Immunotherapy (anti-PD-1, anti-CTLA-4) / BRAF-MEK inhibitors — advanced/metastatic disease (specialist oncology)

Key points

Breslow thickness is the dominant prognostic factor — hence excision (not partial) biopsy. Nodular melanoma can lack the classic ABCDE features (amelanotic, symmetrical) but grows fast. Subungual melanoma: a pigment streak with Hutchinson sign that does NOT grow out.

Monitor & prognosis

Skin and nodal surveillance; staging investigations by thickness.

Excellent for thin lesions; falls sharply with increasing Breslow thickness/metastasis.

Source: NICE NG12; NICE NG14 (melanoma)