Scalp melanoma is associated with high mitotic rate and is a poor prognostic factor for recurrence and outcome

Abstract

A small subset of head and neck melanoma, scalp melanoma comprises 3-5% of all cutaneous melanomas. So far, small numbers of researches on scalp melanoma have yielded controversial results. In this trial, we aimed to define the histopathological and clinical features specific to scalp melanoma and to compare them with melanomas that occurred on other sites by using a large group of patients from a single institution. The data of 93 patients with scalp melanoma and 1076 patients with melanomas on other sites were analyzed retrospectively. The median age of the patients was 53 (range 18-83) years. The scalp melanomas were found more frequently in male patients (79.6 vs. 52.0%, P=0.001) and they tended to have nodular histology (41.1 vs. 29.2%, P=0.01), with a higher mitotic rate (>3/mm(2)) (56.9 vs. 40.9%, P=0.01). However, the scalp melanoma was not significantly associated with other histopathological parameters, for example, age, Clark invasion level, Breslow thickness, ulceration, regression, lymphovascular invasion, neurotropism, tumor-infiltrating lymphocyte, and BRAF mutation analysis. Besides, no correlation was found between scalp localization and either nodal involvement or metastasis (P>0.05). The scalp patients had poorer survivals compared with those with other sites. The median survival time and 5-year recurrence-free survival rates for scalp and other sites in patients were 15.6 months and 45.1% versus 23.5 months and 63.6%, respectively (P=0.001). Similarly, the median overall survival times and 5-year overall survival rates in scalp and other sites in patients were 25.6 months and 44.1% versus 28.7 months and 62.9%, respectively (P=0.0001). In conclusion, scalp melanoma patients correlate with a high mitotic rate and are associated with poorer survival than patients with melanomas on other sites.