Skin cancers that develop on the back can pose a serious challenge for early detection. Unlike the face, arms, or legs, the back is difficult for individuals to observe regularly, which means lesions may go unnoticed until they become advanced.

For skin cancer screening practitioners, applying a systematic method of dermoscopic assessment—beginning with recognition of asymmetry and then identifying concerning features—helps separate benign lesions from those requiring further investigation.

Melanoma on the Back

Statistics and Risk in Men

The back is one of the most common sites for melanoma, particularly in men. Research shows that men are more likely to develop melanoma on their back than on any other part of the body. In contrast, women most often develop melanoma on their legs.

In Australia, approximately 40% of melanoma cases in men are located on the trunk, and the majority of those occur on the back. This higher incidence is thought to relate to intermittent sun exposure patterns, such as sporting activities, outdoor work, or spending time shirtless during recreation.

Dermoscopic Features of Melanoma on the Back

When assessing pigmented lesions on the back, the first step is to determine whether the lesion is symmetrical in both structure and colour. If symmetry is absent, further attention is required. Key features that suggest malignancy include:

• Multiple colours within a single lesion, such as brown, black, grey, and blue.
  
  
• Irregular clods or dots scattered unevenly across the lesion.
  
  
• Eccentric structureless areas, where one part of the lesion appears homogeneously pigmented but does not match the remainder.
  
  
• Thickened or irregular reticular lines, indicating abnormal pigment network development.
  
  
• Polymorphous vessels, including dotted or linear irregular patterns, visible through dermoscopy.
  
  
• White shiny lines, corresponding to stromal changes.
  
  

The presence of asymmetry plus one or more of these features significantly increases the suspicion of melanoma and warrants further action such as excision or referral.

Basal Cell Carcinoma on the Back

Statistics and Risk

Basal cell carcinoma (BCC) is the most common form of skin cancer in Australia, and while it occurs frequently on the face and neck, the back is also a common site, especially for superficial BCCs. This is particularly important as lesions may remain unnoticed for longer periods compared with those on visible body sites. Around 70% of all non-melanoma skin cancers in Australia are BCCs, and superficial types represent a substantial proportion of cases found on the trunk, including the back.

Dermoscopic Features of BCC on the Back

For BCCs, the same systematic method can be applied. The initial step is again to look for asymmetry. If the lesion is not symmetrical, the practitioner should examine for specific features that suggest BCC, such as:

• Arborising or branching vessels, often crossing the lesion.
  
  
• Fine telangiectasia or dotted vessels, distributed irregularly.
  
  
• White shiny lines or structureless areas, indicating fibrosis within the lesion.
  
  
• Ulceration or surface erosion, sometimes surrounded by a rolled border.
  
  
• Pigmented clods, which may be present in pigmented variants of BCC.
  
  

These findings, especially when combined in an asymmetrical distribution, are highly supportive of a BCC diagnosis. On the back, superficial BCCs may present as large, irregularly shaped patches with both vascular and pigmented components.

Screening Considerations for the Back

Thorough screening of the back is essential, as patients often remain unaware of developing lesions. Practical steps include:

• Full-skin checks must always include the back, with dermoscopy used for any pigmented or vascular lesions.
  
  
• Photographic monitoring is highly beneficial in patients with many naevi, allowing new or changing lesions to be tracked over time.
  
  
• Patient education is critical: individuals should be encouraged for self skin check, occasionally check their back and report anything new, enlarging, or bleeding.

Conclusion

The back is a high-risk site for both melanoma and basal cell carcinoma, particularly in men. Melanomas in this region are more common in men than on any other body site, and BCCs frequently appear as superficial lesions on the trunk, including the back.

By starting with an assessment of symmetry, and then recognising specific dermoscopic features—such as irregular clods, multiple colours, eccentric structureless zones, polymorphous vessels, or white shiny lines for melanoma, and arborising vessels, ulceration, and pigmented clods for BCC—skin cancer screening practitioners can detect malignancies on the back at an earlier stage.

Structured dermoscopic assessment, combined with patient education and regular full-skin checks, ensures this difficult-to-see site is not overlooked and that outcomes for patients are significantly improved.