Ultra-High-Frequency Ultrasound of Melanoma Excision Scars for Detection of Clinically Occult Local Recurrence: A Single-Center Retrospective Study

Background: High- and ultra-high-frequency ultrasound (HFUS/UHFUS) may enhance early detection of clinically occult local recurrence at melanoma excision scars, where postoperative fibrotic or inflammatory changes can obscure subtle dermal-subcutaneous foci. Methods: This single-center retrospective observational study included all consecutive patients with histologically confirmed cutaneous melanoma who underwent HFUS/UHFUS assessment of the excision scar between November 2024 and October 2025 at a tertiary referral center. Examinations were performed with a Vevo 3100 system using a 48-70 MHz linear transducer by an experienced radiologist (>10 years), following a standardized institutional protocol. Scars were classified as benign remodeling, indeterminate, or suspicious/highly suspicious according to predefined morphologic and vascular features. Suspicious/highly suspicious findings were referred for biopsy/excision; indeterminate findings underwent short-interval follow-up; benign-appearing scars were monitored per protocol. Histopathology and/or longitudinal follow-up served as reference standards. Results: Among 320 patients (730 examinations), 53 scars were categorized as suspicious/highly suspicious; recurrence was histologically confirmed in 50 cases, while 3 represented fibroblast-rich extracellular matrix remodeling. All recurrences were clinically occult at imaging. No false negatives were observed within the available follow-up of ultrasound-negative scars (median 12 months; range 3-12). Sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy were 100%, 98.9%, 94.3%, 100%, and 99.1%, respectively. Conclusion: In an expert setting, HFUS/UHFUS provides highly reliable detection of subclinical local recurrence at melanoma excision sites and robust discrimination from benign postoperative changes, supporting its integration as an adjunct tool in specialized follow-up pathways.