Lentigo Maligna: Diagnosis and Treatment
Section snippets
Epidemiology and patient demographics
Originally described by Hutchinson in 191211 and further defined by Dubrueilh12, 13 LM and LMM are diseases that typically present in the sixth and seventh decades of life.14 Although the average age of presentation for other subtypes of malignant melanoma has been estimated to be in the 45- to 57-year range,15, 16 the average age of presentation for LM and LMM falls slightly higher, in the 66- to 72-year range.15, 16, 17 Because of varying degrees of sun exposure to the population, the
Clinical presentation/diagnosis
LM and LMM in many ways continue to present a clinical conundrum. Although the original description by Hutchison11 describes a tan-colored lesion, hence the term Hutchison's melanotic freckle, savvy clinicians are aware of the vast differences in presentation that are associated with this disease. The typical presentation is that of a tan colored macule located on chronically sun-damaged skin on the head and neck of middle-aged and elderly patients (Fig. 1). Lesions, however, can vary in
Histology
The histologic hallmark in diagnosing LM is the presence of an increased number of atypical melanocytes at the basal layer of the epidermis in small nests or single cells, usually with extension into the periadnexal structures (Fig. 2).4, 27 Melanocytic atypia can be characterized in various ways, including but not limited to the presence of dendritic melanocyte processes, multinucleated melanocytes, or cytoplasmic retraction artifact.28, 29 Other observed histologic markers that can aid in the
Treatment
Treatment of LM and LMM has evolved over the years. Although surgical excision remains the gold standard, the methods by which excision is undertaken have changed significantly. Various methods are used, including direct excision with margins, Mohs micrographic surgery, and staged excision. Recurrence rates reported using these various methods range from 0.5% to 33% depending on technique.4, 32, 33, 34 Other less-invasive treatment methods including topical and physical nonspecific destructive
Radiotherapy
Radiotherapy for LM first was described in the European literature by Miescher in the mid 1950s.36, 37 Widely accepted and used for primary treatment of LM and adjuvant treatment of LMM in Europe, this treatment modality has been speculated to be at least as effective as surgical excision.38 Published recurrence rates have been found to be between 0% and 13%, with multiple studies having follow-up of 2 years or greater.10, 39, 40
Despite the use of radiotherapy as a primary treatment abroad, it
Surgical therapy
Surgical excision remains the gold standard for treating LM. Over the years, several different surgical techniques have been developed and applied to the treatment of LM. These include standard excision with margins, Mohs micrographic surgery, and staged excision procedures. The trend to develop improved techniques can be attributed to efforts to better control the clinically ill-defined margins of the disease while maximizing tissue sparing, as many of these lesions occur in cosmetically
Summary
The treatment of LM and LMM is a difficult problem that crosses specialty lines. As these lesions tend to occur most often in the head and neck, function and cosmesis are of paramount concern. Issues confounding the diagnosis and treatment of the disease include the diffuse nature of the lesions and confusing nomenclature, which can lead clinicians away from the reality that LM is melanoma in situ. Various treatment options are available depending on patient preference and goals of therapy.
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