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As well as conventional excision down to fat , complete biopsy of a lesion may be achieved through deep shave excision ( saucerisation ). Limit the use of saucerisation biopsy to in situ or superficially invasive melanomas to preserve prognostic features and optimise accurate planning of therapy . The authors strongly advise against shave excision of raised lesions because there is likely to be a dermal component and thus a high risk of transecting the excision specimen at the base of the lesion , leaving the base / deep aspect of it behind .

PARTIAL BIOPSY Avoid partial incisional biopsy of suspected melanoma lesions where possible , as only a portion of the lesion will be present for histopathological diagnosis . In cases where removal of the entire lesion is not feasible because of the size of the lesion or its location , partial incisional biopsy may be acceptable . If the lesion is large , multiple biopsies may be needed to reduce the risk of misdiagnosis due to sampling error .

THE ROLE OF SENTINEL LYMPH NODE BIOPSY SLNB describes the process that maps and excises the regional lymph nodes that receive lymphatic drainage from the site of the primary melanoma lesion . Excised lymph nodes undergo histopathological assessment to look for evidence of cutaneous spread of melanoma . SLNB should occur in conjunction with wide local excision of the primary tumour . If SLNB is performed after a wider excision , lymphatic mapping is unreliable because of disruption of regional tissue . The presence of melanoma in sentinel lymph nodes provides important prognostic information .

SLNB is currently recommended when the primary melanoma tumour has a Breslow thickness of 1mm or greater . SLNB should be considered in more superficial tumours ( 0.8mm or more ) in the presence of highrisk features , such as tumour ulceration at diagnosis . 58 However , there is strong evidence for SLNB in patients with melanoma of 0.8-1mm thickness , regardless of ulceration .

34 , 59

The Cancer Council Australia guidelines recommend SLNB for tumours less than 1mm thick , when pathological features of ulceration or mitotic rate of greater than 1mm 2 are present . 60 Refer all patients where a SLNB may be appropriate for multidisciplinary care .

Less invasive investigations , such as ultrasound , were previously suggested for the assessment of regional lymph nodes in cutaneous melanoma . However , such methods have been demonstrated to be inferior to SLNB . A multicentre trial demonstrated that ultrasonography detected only 6.6 % of sentinel lymph node positive patients . 61 The sensitivity of other imaging modalities , such as CT and PET / CT for the detection of melanoma metastases that are not clinically apparent is even lower . 61 SLNB is the gold standard for assessment and staging of regional lymph node involvement in melanoma .

SLNB is a powerful tool for assessing the prognosis of a patient with

Figure 7 . American Joint Committee on Cancer ( AJCC ) melanoma staging .

Table 1 . Histopathological features of melanoma by subtype

Pattern of radial growth phase

Dominant cell type in radial growth phase

Dominant cell of vertical growth phase

Superficial spreading melanoma

melanoma and has recently begun to play a role in planning for adjuvant systemic therapies .

Staging

Once the diagnosis of melanoma is made , accurate staging is essential to guide decisions on treatment and assessment of prognosis . The American Joint Committee on Cancer Staging Manual ( eighth edition ) outlines melanoma staging ( see box 6 and figure 7 ). 34

MANAGEMENT

WIDE local excision of the primary tumour , with an adequate surgical margin as determined by melanoma depth , is an essential part of definitive treatment for all primary cutaneous melanomas . In localised disease ,

Lentigo maligna melanoma

without regional lymph node or distal metastatic involvement , adequate surgery represents definitive melanoma treatment . In more widespread disease , recent advancements in immunotherapy and targeted molecular therapy have provided significant survival benefits .

Surgery

After initial excision biopsy , the radial excision margins , measured clinically from the edge of the melanoma , should be 5-10mm ( measured with good lighting and magnification ) with the aim of achieving complete histological clearance ( see figure 8 ). 60 Most primary melanomas can be treated as an outpatient under local anaesthesia or as a day-case .

Acral lentiginous melanoma

Nodular melanoma

Diffuse pagetoid Lentiginous Lentiginous Nil radial growth

Epithelioid Epithelioid , spindle , dendritic ( rare )

Spindle , epithelioid or dendritic

Epithelioid Spindle and epithelioid Spindle and epithelioid Epithelioid

Other features Regression common Desmoplasia common Desmoplasia common Desmoplasia common Adapted from Liu V 2021 49

Reproduced with permission from Jeffrey E Gershenwald JE et al Melanoma staging : Evidence-based changes in the American Joint Committee on Cancer eighth edition cancer staging manual 2017 CA Cancer J Clin 67 ( 6 ): 472-492 .

MELANOMA IN SITU Melanoma in situ of non-lentigo maligna type is likely to be completely excised with 5mm margins whereas lentigo maligna ( see figure 9 ) may require wider excision . Minimum clearances from all margins should be stated / assessed . Consideration should be given to further excision if necessary ; positive histological margins are unacceptable . 60

Depth of excision in usual clinical practice is excision down to , but not including , the deep fascia unless it is involved or has been reached during the diagnostic excision . For body sites where there is particularly deep subcutis , it is usual practice to excise to a depth equal to the recommended lateral ( radial ) excision margins for that

Box 6 . Melanoma staging

• Localised disease with no evidence of metastasis ( stages I and II ).

• Presence of regional node disease ( stage III ).

• Presence of distant metastatic disease ( stage IV ).

Box 7 . Surgical margins for invasive melanoma

• Breslow thickness less than 1.0mm ( pT1 ) melanoma : 1cm peripheral margins .

• Breslow thickness 1.01mm- 2.0mm ( pT2 ) melanoma : 1-2cm peripheral margins .

• Breslow thickness 2.01mm- 4.0mm ( pT3 ) melanoma : 1-2cm peripheral margins .

• Breslow thickness greater than 4mm ( pT4 ) melanoma : 2cm peripheral margins .

specific melanoma ; in these cases it is not deemed necessary to excise right down to fascia .

INVASIVE MELANOMA Surgical margins for invasive melanoma are determined by depth of invasion ( see box 7 ). 60

As discussed earlier , patients with melanoma tumours with a Breslow thickness of 0.8-1mm may be appropriate for SLNB . The authors suggest referring these patients for multidisciplinary assessment and consideration of SLNB before wide local excision of the primary tumour .

COMPLEX LESIONS Some tumours may be incompletely excised despite using the above recommended margins . These include melanomas occurring in severely sun damaged skin ( for example , ALM ) and those with difficult-to-define margins ( for example , amelanotic and desmoplastic melanomas ). 60 In these categories , the presence of atypical melanocytes at the margins of excision should be detected by comprehensive histological examination ( including immunohistochemical staining ) and followed by wider excision as appropriate . 60 Alternatively , staged serial excision ( also known as ‘ slow Mohs ’ surgery , see figure 10 ) may be utilised to achieve complete histological clearance of melanoma in situ / lentigo maligna . Preoperative mapping of the extent of some lesions with confocal microscopy may be useful and is available in some centres . Referral to a specialist melanoma centre or discussion in a multidisciplinary meeting should be considered for difficult or complicated cases .

Adjuvant radiotherapy

Cancer Council Australian Melanoma Management Guidelines recommend consideration of adjuvant radiotherapy for patients with histopathological high-risk features , such as extranodal tumour extension , following regional lymph node dissection , if potentially effective systemic therapy is not available . 63

Adjuvant systemic therapies

Adjuvant systemic therapy is used in patients with resected stage III