The Usefulness of High-Frequency Ultrasound in the Management of Patients with Giant Congenital Melanocytic Nevi: A Cohort Prospective Study.

Objectives: Congenital melanocytic nevi (CMN) exhibit various clinical presentations. Dermoscopy and confocal microscopy only assess the superficial dermis. Magnetic resonance imaging cannot evaluate skin layers comprehensively. High-frequency Doppler ultrasound (HFUS) can define the extent of melanocytic lesions and suggest patterns of potential complications. The objective of the study is to evaluate HFUS characteristics of patients with CMN and, secondarily, to study the utility of HFUS in evaluating proliferative nodules and enlarged lymph nodes.

Methods: A prospective study of patients with multiple and non-small CMN between January 2016 and June 2021 was conducted. Clinical imaging and HFUS were routinely used to follow up on distinctive areas. A retrospective analysis of HFUS images and correlation with presentation was performed.

Results: Seventy-one patients with CMN, 149 HFUS scans. Median age: 14 years (IQR: 8 months-79 years), 59% female. Large/giant nevi n = 44 (61.9%). CMN affected the epidermis/dermis in 51 (71.8%), hypodermis in 17 (24%), and muscle in 3 (4.2%). Thirteen patients (18.3%) had nodular lesions; 1 showed atypical vessels on HFUS, which was confirmed histologically as an atypical proliferative nodule.

Limitations: Heterogeneity of patients and retrospective analysis.

Conclusions: HFUS allows the characterization of non-small CMN by assessing depth and diagnosing complications such as melanomas and enlarged lymph nodes.