Subungual Melanoma: A Descriptive Study of 34 Patients

Subungual melanoma constitutes a diagnostic challenge because it often has an atypical clinical presentation. The aims of this study were to revise the clinical and pathologic characteristics of patients with subungual melanoma diagnosed at a tertiary care university hospital and analyze the factors potentially associated with a delayed diagnosis. We analyzed data for 34 patients diagnosed with subungual melanoma at our hospital over a period of 20 years. The study population comprised 18 women and 16 men with a median age at diagnosis of 66 years. Only 5 of the patients had longitudinal melanonychia when examined at the dermatology department. At the time of diagnosis, 19 of the 34 patients had invasive melanoma (median Breslow thickness, 3.70mm); 16 had ulceration and 8 had regional lymph node involvement. Five patients had subungual melanoma in situ at diagnosis. The median time from appearance of the lesions to consultation at a primary care center was 15 months; the corresponding time from primary care consultation to diagnosis at our hospital was 5.5 months. Lesions located on the toes were more likely to be ulcerated (P=.017) and to be accompanied by regional lymph node involvement at diagnosis (P=.012). The factors associated with a longer diagnostic delay in patients with subungual melanoma were absence of melanonychia as a presenting feature and involvement of the toes.