Epidemiology
Acral melanoma (AM) accounts for a disproportionately higher percentage of cases among individuals with darker skin tones, including those of African, Asian, and Hispanic descent [PMID:41650285].
Clinical Presentation
Clinically, AM typically presents as asymmetric brown macules with irregular borders and variable pigmentation [PMID:41650285].
Diagnosis
Although not required for diagnosis or staging protocols, Ki-67, a cell proliferation marker, can provide additional prognostic information beyond histopathological analysis [PMID:41861758].
A study identified 69 differentially expressed miRNAs in serum exosomes from patients with acral melanocytic tumors, suggesting these miRNAs could potentially aid in the early and non-invasive diagnosis of acral melanoma [PMID:42001282].
Differential Diagnosis
The research highlighted differential expression patterns of miRNAs, with 14 up-regulated and 55 down-regulated miRNAs, indicating these profiles could help distinguish between benign and malignant acral melanocytic tumors [PMID:42001282].
Management
Given that elevated Ki-67 indices predict poorer outcomes, incorporating Ki-67 assessment into follow-up protocols could inform more aggressive management approaches [PMID:41861758].
Prognosis & Follow-up
Elevated Ki-67 indices in acral cutaneous melanomas (ACM) correlate with unfavorable outcomes, suggesting its utility as a prognostic marker [PMID:41861758].
AM is associated with poorer prognosis and lower survival rates compared to non-AM melanomas, likely due to delayed diagnosis and greater tumor thickness at presentation [PMID:41650285].
Key Recommendations
Given the potential of exosomal miRNAs as stable biomarkers, future clinical studies are advised to validate their utility in routine diagnostic protocols for acral melanoma [PMID:42001282]. (Evidence: Expert opinion)
References
1 Asato MA, Contel IJ, Moraes Neto FA, Ocanha-Xavier JP, Oliveira NSC, Fung MA et al.. Ki-67 staining pattern as a prognostic biomarker for advanced acral melanoma. Anais brasileiros de dermatologia 2026. link 2 Russolillo JK, Schaedler A, Hsia B, Silberstein PT, Tauseef A, Torbenson E. Comprehensive Genomic Profiling of Acral Melanoma: Insights From the AACR Project GENIE Database. The American Journal of dermatopathology 2026. link 3 Zhu T, Wang J, Wang Y, Wen C, Han Y, Hu Y et al.. Differential expression analysis of serum exosome miRNAs in acral melanocytic tumor. Pakistan journal of pharmaceutical sciences 2026. link