14th July 2026

Investigations

A vitamin D level should be checked at diagnosis in all patients with melanoma

Dermoscopy: atypical globules and dots, atypical network, blue-white veil

Biopsy and histopathology:

• Biopsy: full-thickness excision of lesion with 1-3mm margin 
  • Prognostic indicators: Breslow’s thickness (depth from granular cell layer to deepest tumour penetration in dermis), ulceration, mitotic count, lymphovascular invasion, microscopic satellites, serum LDH
  • Abnormal and severe melanocytic proliferation in epidermis +/- dermis, asymmetrical growth pattern

Immunohistochemistry: markers used in analysis include Melan-A/MART-1, S-100, HMB-45, SOX10, MiTF and tyrosinase. 

BRAF mutation testing should be performed in those with stage IIIB onwards.

Staging of cutaneous melanoma:

• Localised disease (stage I-III)
• Regional disease (stage III)
• Distant metastatic disease (stage IV)

Clark’s level

• Level 1: in-situ melanoma
• Level 2: invasion within papillary dermis
• Level 3: invasion filling papillary dermis
• Level 4: invasion within reticular dermis

Management 

Dependent on subtype of melanoma and stage of cancer. 

In patients where surgery is not indicated (i.e., multi-comorbid patients or difficult tumour location), topical chemotherapy (imiquimod), or radiotherapy may be used. 

In those with melanoma in situ, topical imiquimod should be considered if removal of 5mm margins would cause disfigurement. 

Unresectable advanced stage (stage III or IV): 

• Systemic therapy (nivolumab and ipilimumab, nivolumab or pembrolizumab)
• Where surgery cannot be performed for metastasis, talimogene laherparepvec or electrochemotherapy may be indicated in some patients.

Surgical management

Early stage (melanoma in situ, stage I and stage II): 

• Wide local excision with 5-10 mm margins (5mm for lentigo maligna). 
• Mohs’ surgery can be considered in those with minimally invasive tumours on sites such as the ear or face. 
• Sentinel lymph node biopsy (SNLB) may be used in those with stage I or stage II, and is an important prognostic factor in this patient group. 

Resectable advanced stage (stage III or IV): 

• Wide local excision PLUS adjuvant systemic therapy (nivolumab, pembrolizumab or dabrafenib and trametinib).