The principal objectives of this session are to allow experienced skin cancer clinicians the opportunity to reflect upon and review diagnosis, treatment and follow-up of lentigo maligna, with an emphasis on the role of new diagnostic and treatment techniques.
Lentigo maligna is a form of insitu melanoma. The incidence of the condition is increasing in fair skinned populations across the world, which relates to increasing sun exposure and longevity. When lentigo maligna becomes invasive it is referred to as lentigo maligna melanoma.
Lentigo maligna may present with features similar to other subtypes of melanoma with asymmetry, pigment variation and border irregularity. The condition gradually develops over a long period of time, with the pigmented lesion expanding in diameter. Amelanotic lentigo maligna is a particular diagnostic pitfall, and may resemble Bowman's disease, actinic keratoses, superficial basal cell carcinoma or eczema. Lentigo maligna has a strong relationship with UV exposure and usually occurs on sun exposed surfaces, and most often in elderly patients around the head and neck, although it can be found on other locations.
Lentigo maligna is considered to be a true precursor of melanoma, in that most cases, given enough time, will progress to lentigo maligna melanoma. The exact percentage of cases that progress to an invasive tumour is unknown, and the lifetime risk has been estimated to be 4.7% of 45 years of age and 2.2% for a 65 year old. Once lentigo maligna melanoma develops, its prognostic features are similar to other forms of invasive melanoma. The standard treatment of lentigo maligna is complete surgical excision of the lesions, but clinical challenges arise from this.
This session will cover clinical and dermoscopic features of lentigo maligna. The use of single and multiple diagnostic biopsies, selection of sites of tissue sampling will be discussed, and treatment options will be outlined. The role of excisional surgery and the use of radiotherapy and imiquimod will be highlighted. Follow up protocols will be reviewed.