Review: Dermoscopic Patterns May Improve Differentiation of Acral Melanoma and Nevi

A systematic review and meta-analysis in JAMA Dermatology provides updated evidence on dermoscopic features that differentiate acral lentiginous melanoma (ALM) from benign acral nevi.

Investigators searched Embase, PubMed, Web of Science, MEDLINE, and the Cochrane Library for studies published from January 1970 through March 2023 that evaluated dermoscopic patterns in acral melanocytic lesions. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, reviewers extracted data on dermoscopic features and analyzed pooled prevalence differences using random-effects models. The final analysis included 41 studies comprising 8,845 acral nevi from 35 studies and 801 cases of ALM from 18 studies.

The parallel ridge pattern emerged as the most diagnostically informative feature for ALM, observed in 79.6% of melanomas (95% CI, 71.4% to 87.8%) compared with 0.6% of acral nevi (95% CI, 0.3% to 0.9%), yielding a pooled difference of −77.3% (95% CI, −85.0% to −69.6%; P < 0.001). Multicomponent structures were also significantly associated with ALM, appearing in 45.8% of melanomas (95% CI, 19.3% to 72.2%) versus 5.0% of nevi (95% CI, 3.7% to 6.2%), with a pooled difference of −38.5% (95% CI, −65.7% to −11.2%; P = 0.01).

Patterns traditionally associated with benign acral lesions were more common in nevi. The parallel furrow pattern was reported in 51.8% of nevi (95% CI, 46.7% to 56.8%) vs. 8.9% of ALM (95% CI, 5.3% to 12.5%), while latticelike patterns were present in 13.0% of nevi (95% CI, 10.6% to 15.5%) and 2.7% of ALM (95% CI, 1.0% to 4.5%). Other dermoscopic structures showed inconsistent or nonsignificant associations.

While the parallel ridge and parallel furrow patterns remain key diagnostic indicators of ALM and benign acral lesions, this systematic review and meta-analysis establishes the additional diagnostic significance of multicomponent and latticelike features" the authors wrote. "Nearly 20% of ALM lacked the parallel ridge pattern, demonstrating the need for new specific features for melanoma diagnosis. These findings provide evidence-based benchmarks to potentially improve diagnostic accuracy, guide dermoscopy training, and enhance early detection of ALM. Nearly 20% of ALM lacked the parallel ridge pattern, demonstrating the need for new specific features for melanoma diagnosis.”

Okwara C, et al. JAMA Dermatology. 2026. Doi: