Acral Lentiginous Melanoma
Soheil Sam Dadras, MD, PhD
Nicole Carreau
Key Facts
Terminology
Acral melanoma that grows in a lentiginous pattern
Clinical Issues
< 5% of all malignant melanomas
Most often on sole of foot or subungual region
Microscopic Pathology
Lentiginous proliferation of atypical melanocytes with rare pagetoid scatter
ALM in situ may present with very few atypical melanocytes
Nesting at dermal-epidermal junction
Rare to absent in early lesions, prominent and confluent in late lesions
Nests are irregular in size and shape, randomly alternate with single melanocytes
Cells show elongated, ovoid hyperchromatic nuclei with little cytoplasm
 The heel of this patient shows a dark brown plaque with early depigmentation  . (Courtesy J. Finch, MD.) |
 Lentiginous growth of atypical melanocytes  is seen in this early in situ lesion. Only rare upward scatter  of atypical melanocytes is identified. A Meissner corpuscle  is seen in the dermis. |
TERMINOLOGY
Abbreviations
Acral lentiginous melanoma (ALM)
Definitions
Form of cutaneous melanoma that microscopically grows in a lentiginous array and occurs on acral sites
