Functional surgery for invasive nail apparatus melanoma: A cohort study and systematic review.

BACKGROUND

Surgical management of nail apparatus melanoma (NAM) has evolved from amputation to digit-preserving functional surgery, supported by oncologic safety in non-invasive disease. However, indications and outcomes in invasive melanoma remain unclear. We evaluated a standardized institutional protocol for functional surgery in invasive NAM and performed a systematic review of the literature.

METHODS

Patients with primary invasive NAM treated between 2021 and 2025 were reviewed. Preoperative MRI was used to assess bone involvement. Functional surgery was performed when no bone invasion was identified, across a range of Breslow thicknesses. Oncologic outcomes were analyzed. A systematic review of studies reporting functional surgery for invasive NAM was also conducted.

RESULTS

Twenty-seven patients were included (median Breslow thickness, 1.8 mm). Tumor stages were T1 (n = 9), T2 (n = 7), T3 (n = 6), and T4 (n = 5); three patients had nodal metastasis. Pathology confirmed absence of bone invasion in all cases, yielding an MRI negative predictive value of 100%. Median tumor-to-bone distance was 1.75 mm and showed no correlation with Breslow thickness. Over a median follow-up of 18 months, three recurrences occurred (one regional lymph node, two distant), all distant recurrences in node-positive patients. No local recurrence was observed. The estimated two-year locoregional recurrence-free survival rate was 94.4%. The systematic review identified no study defining clear indications of functional surgery for invasive lesions.

CONCLUSIONS

Functional surgery appears oncologically safe for invasive NAM without radiologic bone involvement across a range of tumor thicknesses. Preoperative MRI may aid patient selection. Larger studies with longer follow-up are warranted.