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

Application of fluorescence in situ hybridization in distinguishing acral melanoma in situ from acral junctional melanocytic nevus on the volar skin in Japanese patients

“…It is often difficult for dermatologists and pathologists to diagnose AM accurately in the early stages, primarily because of the faint changes of lesions or discrepancy between the clinical or dermoscopic findings and pathological findings. Even in clinically typical lesions of AM, such as large, asymmetrical lesions with color variegation, sparse melanocytes with subtle or no atypia may sometimes be observed on pathological examination, which makes it difficult to diagnose them as malignant lesions 9–12 . Conversely, in small lesions, symmetrical pigmented macules without color variegation may appear clinically to be benign; however, melanocytic proliferation with pagetoid spread or numerous confluent nests of atypical melanocytes are sometimes observed pathologically, thus making it difficult to diagnose them as benign lesions 13,14 …”

“…Even in clinically typical lesions of AM, such as large, asymmetrical lesions with color variegation, sparse melanocytes with subtle or no atypia may sometimes be observed on pathological examination, which makes it difficult to diagnose them as malignant lesions. [9][10][11][12] Conversely, in small lesions, symmetrical pigmented macules without color variegation may appear clinically to be benign; however, melanocytic proliferation with pagetoid spread or numerous confluent nests of atypical melanocytes are sometimes observed pathologically, thus making it difficult to diagnose them as benign lesions. 13,14 Recent advancements in molecular genetic technique have elucidated the genetic features of various clinical subtypes of melanoma, which can aid in establishing an accurate genetic diagnosis.…”