The umbilicus: a rare site for melanoma. Clinical considerations in two cases. Case reports.

The umbilicus is a rare site for malignant melanoma. We report two cases of umbilical melanoma and analyse the mechanisms of diffusion of the neoplasm in relationship to the arterial, venous, and lymphatic anatomy of the region. Because of the peculiarity of these connections, we propose a revision of the concept of melanoma stage for the umbilical region.