Clinicopathologic features and surgical management of primary umbilical melanoma: a case series

BACKGROUND: Primary umbilical melanoma is an uncommon tumor that is poorly described in the medical literature. The umbilical region is a particular anatomic site owing to the presence of embryonal remnants, which can be a potential metastatic pathway, as well as the braided lymphatic network drainage. Hence, primary malignant neoplasms affecting the umbilicus require a different and more radical surgical approach compared with other melanomas. CASE PRESENTATION: In this report, we describe a series of three patients of Caucasian ethnicity who presented with primary umbilical melanoma at the National Cancer Institute of Naples, Italy. All patients underwent wide excision of the tumor including the underlying peritoneum. No surgical complications, either immediate or delayed, were observed in any of the patients. Sentinel lymph node biopsy was negative in two cases. Two of the patients developed metastatic disease and died after systemic medical therapy. The other patient is currently in follow-up, and remains disease-free after 21 months. CONCLUSIONS: The umbilicus has vascular and embryological connections with the underlying peritoneum, so that early visceral involvement is more likely to occur with primary umbilical melanomas. As such, tumor resection including the underlying peritoneum is required to avoid local relapse, whilst sentinel lymph node biopsy appears to be of poor diagnostic value.