Background: Patients with subungual melanoma (SM) often experience delayed diagnosis and present with deep primary lesions. Breslow depth of the primary lesion is often unknown before definitive resection, thus complicating treatment planning.
Methods: Patients with SM treated at our institution from 1992 to 2004 were identified from our prospective melanoma database. Clinical and pathologic factors were reviewed; Student t test and Kaplan-Meier method were used for statistical analysis.
Results: Forty-nine patients were identified; most were female (63%). The median age was 66 years (range 24 to 83). The most common site was the great toe (n = 21), followed by the thumb (n = 15). Eight patients had in situ disease; 6 were treated initially with wide local excision, and 4 of these eventually required amputation. The median Breslow depth of invasive lesions was 2.1 mm (range .2 to 11). Toe lesions were thicker than finger lesions (mean 3.5 vs 2.5 mm, P = .005). Patients with invasive SM of the toe had a less favorable outcome than those with finger lesions (5-year overall survival 40% vs 72%, respectively; P = .05). Sentinel lymph node (SLN) biopsy was performed in 30 patients and was positive in 5 (17%); all underwent completion lymphadenectomy. Median Breslow depth in patients with positive SLN was 4 mm (range 1.2 to 11). Four of 5 patients with positive SLN developed recurrence (median 16 months); 3 patients died of disease within 40 months.
Conclusions: Patients with SM present distinct therapeutic challenges. They continue to present with deep primary melanoma, particularly on the toe. Undertreatment of early disease is associated with local recurrence.