Melanoma of the Umbilicus: A Patient Report, Precaution in Operative Strategy, and the First Histopathological Review of Published Cases.

Umbilical melanoma is extremely rare. Among the past English reports on umbilical melanoma, there are only 8 reports in which histopathology was described in detail, and there has been no report with a review of the histopathology of previously reported cases. We experienced a case of umbilical melanoma and reviewed previously reported cases including our case. Because of the anatomical location, it is difficult to become aware of the umbilical melanoma unless there are some concomitant symptoms such as discharge or swelling. Even with these symptoms, patients tend to postpone a hospital visit for unknown reasons, resulting in increased risk of tumor growth and metastasis. When performing resection of umbilical melanoma, a portion of the peritoneum should also be removed. Sentinel lymph nodes can be axilla or inguinal lymph nodes. There is a possibility of metastasis to the preoperative abdominal cavity or to nearby skin through hematogenous spread. Preoperative evaluation of tumor spread and postoperative observation are important for umbilical melanoma in order to detect recurrence or metastasis because of its unique anatomical location.