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ALL / Dermatology
Malignant melanoma
Malignant melanoma
There are four main subtypes of melanoma. Nodular melanoma has the worst prognosis due to early vertical growth whilst the other forms tend to have an initial radial growth phase.| Superficial spreading | Nodular | Lentigo maligna | Acral lentiginous | |
|---|---|---|---|---|
| Frequency | 70% of cases | Second commonest | Less common | Rare overall (but most common in people with darker skin) |
| Typically affects | Arms, legs, back and chest, young people | Sun exposed skin, middle-aged people | Chronically sun-exposed skin, older people | Nails, palms or soles |
| Appearance | A growing mole with diagnostic features listed above | Red or black lump which may bleed or ulcerate | A slowly enlarging pigmented macule/patch | Subungual pigmentation (Hutchinson's sign) or on palms or feet |
There are other rare forms of melanoma including desmoplastic melanoma, amelanotic melanoma, or melanoma arising in other parts of the body such as ocular melanoma.
The main diagnostic features (major criteria):
| Secondary features (minor criteria)
|
Additional commonly used criteria (ABCDE):
- Asymmetry
- Border irregularity
- Colour variation
- Diameter >6mm
- Evolving lesion
Treatment
- Suspicious lesions should undergo excision biopsy with a narrow margin (approximately 2mm). The lesion should be removed completely. Incision biopsy is avoided unless the lesion is large or in a difficult anatomical site.
- Once the diagnosis is confirmed the pathology report should be reviewed (Breslow thickness is the most important prognostic factor; ulceration is also important) to determine further management:
Margins of excision - related to Breslow thickness
| Melanoma in situ | 0.5cm |
| Lesions ≤1mm thick | 1cm |
| Lesions 1-2mm thick | 1-2cm (depending on site) |
| Lesions >2mm thick | 2cm |
Further management
- Sentinel lymph node biopsy:
- Offered for Breslow thickness ≥1mm
- Consider for 0.8–1mm if high-risk features (e.g. ulceration)
- Imaging: if clinically indicated (e.g. suspected metastases)
- Adjuvant therapy (stage II–III or high-risk disease):
- Anti-PD-1 immunotherapy (e.g. pembrolizumab, nivolumab)
- Targeted therapy (BRAF/MEK inhibitors) if mutation-positive
- Lymph node management:
- Completion lymph node dissection is no longer routine after positive sentinel node
- Nodal surveillance ± systemic therapy is preferred
+PassMedicine Notes
There are four main subtypes of melanoma. Nodular melanoma has the worst prognosis due to early vertical growth whilst the other forms tend to have an initial radial growth phase.
_ Superficial spreading _ Nodular _ Lentigo maligna _ Acral lentiginous | Frequency _ 70% of cases _ Second commonest _ Less common _ Rare overall (but most common in people with darker skin) | Typically affects_ Arms, legs, back and chest, young people _ Sun exposed skin, middle-aged people _ Chronically sun-exposed skin, older people _ Nails, palms or soles | Appearance _ A growing mole with diagnostic features listed above _ Red or black lump which may bleed or ulcerate _ A slowly enlarging pigmented macule/patch_ Subungual pigmentation (Hutchinson's sign) or on palms or feet |There are other rare forms of melanoma including desmoplastic melanoma, amelanotic melanoma, or melanoma arising in other parts of the body such as ocular melanoma.
The main diagnostic features (major criteria):- Change in size
- Change in shape
- Change in colour_
- Diameter >= 7mm
- Inflammation
- Oozing or bleeding
- Altered sensation|
- Asymmetry
- Border irregularity
- Colour variation
- Diameter >6mm
- Evolving lesion
- Suspicious lesions should undergo excision biopsy with a narrow margin (approximately 2mm). The lesion should be removed completely. Incision biopsy is avoided unless the lesion is large or in a difficult anatomical site.
- Once the diagnosis is confirmed the pathology report should be reviewed (Breslow thickness is the most important prognostic factor; ulceration is also important) to determine further management:
Margins of excision - related to Breslow thickness
Melanoma in situ_ 0.5cm| Lesions ≤1mm thick_ 1cm| Lesions 1-2mm thick_ 1-2cm (depending on site)| Lesions >2mm thick_ 2cm| Further management- Sentinel lymph node biopsy:
- Offered for Breslow thickness ≥1mm
- Consider for 0.8–1mm if high-risk features (e.g. ulceration)
- Imaging: if clinically indicated (e.g. suspected metastases)
- Adjuvant therapy (stage II–III or high-risk disease):
- Anti-PD-1 immunotherapy (e.g. pembrolizumab, nivolumab)
- Targeted therapy (BRAF/MEK inhibitors) if mutation-positive
- Lymph node management:
- Completion lymph node dissection is no longer routine after positive sentinel node
- Nodal surveillance ± systemic therapy is preferred
