Acral lentiginous melanoma

(A) Low power light photomicrograph of an acral lentiginous melanoma shows a thickened stratum corneum, which is characteristic of acral sites. There is a lentiginous array of atypical melanocytes along the dermo-epidermal junction with foci of confluent melanocytic growth (arrows).
(B) Medium power photomicrograph shows extensive pagetoid spread of single cells into the epidermis (arrowheads).