A Population Based Analysis of Melanoma of the External Ear

Malignant melanoma accounts for nearly 75% of all skin cancer deaths, and the incidence is on the rise in the United States. External ear melanoma (EEM) is rare, and there is little long-term data regarding the clinical behavior of this melanoma site. This study analyzes the demographic, clinicopathologic, and survival characteristics of EEM.

The SEER database was queried for EEM cases from 1973 to 2012 (8,982 cases). Data analyzed included patient demographics, incidence trends, and survival outcomes.

External ear melanoma occurred most frequently in the sixth and seventh decades of life. Mean age at diagnosis was 65.5 (±16.8) years. However, the incidence of EEM in adolescents and young adults (ages 15-39 yr) has increased by 111.9% from 1973 to 2012. There was a strong male predilection with a male-to-female ratio of 6.40:1. The most common histologic subtype was malignant melanoma, NOS (46.8%), followed by superficial spreading melanoma (21.4%), and lentigo maligna melanoma (17.9%). The majority of cases were localized at the time of presentation (88.0%), with rare distant metastasis (1.9%). The most common treatment modality was surgery alone (97.6%), followed by surgery with radiotherapy (2.3%). Ten-year disease-specific survival was better among those treated with surgery alone (90.7%), than those treated with surgery with radiotherapy (37.1%) (p < 0.0001). Increasing Breslow's thickness and presence of an ulcerating lesion were both associated with poorer survival (p < 0.0001).

This study represents the largest cohort of EEM. It has an excellent survival outcome with surgery being the treatment of choice.