Acral Lentiginous Melanoma Developing during Long-standing Atypical Melanosis: Usefulness of Dermoscopy for Detection of Early Acral Melanoma

Abstract

Clinical guidelines suggest that suspicious pigmented lesions of the plantar or palmar area require biopsy for early detection of acral melanoma. We present here a case of acral lentiginous melanoma in which various melanocytic atypia was observed at each biopsy site, including focal melanocytic proliferation. We suggest that this atypical melanosis is part of a contiguous phase of invasive tumor growth, which is known as the very early stage of melanoma in situ. In addition, noninvasive dermoscopy has been effective for the early discovery of hidden lesions of acral melanoma.

Improving the Diagnosis and Treatment of Acral Melanocytic Lesions

“…AM in situ can be divided into three histopathologic phases based on number of melanocytes, degree of atypia and distribution within the epidermis [31]. However, the degree of atypia for the diagnosis of early AM is sometimes subtle, as is often the case for atypical melanosis of the foot [32][33][34]. Atypical melanosis of the foot represent lesions with clinical and dermoscopic findings suggestive of AM or AM in situ, but without any histologic evidence of melanoma [32][33][34].…”

Two Spanish cases of atypical melanosis of the foot, an early stage of acral lentiginous melanomain situ

“…A recent article described the case of a long‐standing lesion where histopathology showed acral lentiginous melanoma in the centre, and ‘atypical melanosis of the foot’ in the periphery . This example supports the hypothesis of a chronological progression between these two entities.…”

Acral melanoma of the foot: a study of 9 cases and guidelines update

“…Le MA est considéré comme le type le plus agressif parmi les mélanomes et par conséquent corrélé à un pronostic réservé. Des études récentes ont expliqué ce mauvais pronostic par le diagnostic tardif de ces tumeurs plus que par leur nature [8].…”

“…Il reste le type le plus décrit chez les sujets à peau pigmentée; en Afrique [1] et en Asie [8][9][10][11][12][13]. Chez le caucasien, le mélanome acral est rare [3,6].…”