Plantar melanoma is associated with certain poor prognostic histopathological factors, but not correlated with nodal involvement, recurrence, and worse survival.

BACKGROUND: Plantar surface melanoma affects the Caucasian race less likely than it does other races, e.g., the Asians and the Blacks. So far, small numbers of researches on plantar melanoma have yielded controversial results. The aim of this study was to define the histopathological and clinical characteristics pertinent to plantar melanoma and to compare them with melanomas that emerged in other sites by using a large group of patients from a single institution.

PATIENTS AND METHODS: A total of 104 Turkish Caucasian plantar melanoma patients and 1065 patients with non-plantar melanomas were analyzed retrospectively.

RESULTS: The plantar melanomas were found more frequently in females (p = 0.006) and in older patients (≥ 50 years old) (p = 0.002). Compared to melanomas in other sites, the plantar melanomas tended to have more acral lentiginous histopathology (p = 0.0001), deeper Clark invasion level (IV-V) (p = 0.01), and thicker Breslow depth (≥ 2 mm) (p = 0.05); and the plantar melanoma lesions were more likely ulcerated (p = 0.0001) and were correlated with more lymphovascular invasion (p = 0.001), fewer tumor infiltrating lymphocyte (p = 0.03), and less frequently associated with a preexisting melanocytic nevus (p = 0.01). However, no correlation was found between plantar localization and either nodal involvement or metastasis (p > 0.05). The recurrence free and overall survival times for plantar melanomas were similar to other sites (p > 0.05). 5-year overall survival rate in plantar melanoma patients were 59%.

CONCLUSION: Even though plantar melanoma is associated with certain poor histopathological factors, it is not correlated with nodal involvement, recurrence, and poor survival.