Acral Lentiginous Melanoma. Part I. Epidemiology, Etiology, Clinical Presentation, and Diagnosis

Abstract

This review article focuses on acral lentiginous melanoma (ALM), a rare cutaneous malignancy and the least common subtype of cutaneous malignant melanoma (CMM). ALM exhibits distinct characteristics, such as low overall mutation rates and increased chromosomal alterations. It is associated with worse prognosis, more advanced disease, and lower survival rates compared to other CMM subtypes. The incidence of ALM varies globally, with higher rates in non-white populations, particularly affecting Black, Hispanic, and Asian individuals. Racial disparities may be attributed to a lack of awareness, biological/genetic differences, cultural values, and socioeconomic status. The etiology of ALM remains unknown, but studies suggest a limited impact of UV radiation, potential links to trauma and stress, and a unique tumor immune microenvironment. Diagnostic challenges include varied clinical presentations, with specific biopsy techniques recommended. Clinical research on ALM lacks representation from diverse populations, ultimately limiting its translatability. Understanding the molecular landscape and clinical aspects of ALM will be crucial for improved diagnosis, treatment, and addressing health disparities. LEARNING OBJECTIVES: After completing this learning activity, participants should be able to discuss the epidemiology, etiology, mutational landscape, tumor microenvironment, and clinical presentation of acral lentiginous melanoma (ALM). Moreover, participants should also be able to describe the important racial disparities observed in ALM.

Keywords: acral lentiginous melanoma; clinical; cutaneous oncology; epidemiology; melanoma; mutational landscape; skin of color; tumor immune microenvironment.