Urachus adenocarcinoma mistaken for umbilical incision implant cancer after laparoscopic cholecystectomy: a case report

Umbilical incision implant cancer after LC is rare. Elective cholecystectomy was planned for a 49 years-old female patient with symptomatic gallstones. The patient underwent transumbilical single-port LC after admission to our hospital. Gallbladder specimens were obtained directly through the umbilical puncture hole, and histopathology suggested chronic cholecystitis. Three months after surgery, the patient experienced painful induration in the umbilicus. We initially considered incision scar hyperplasia complicated with pain, and used drugs to treat it conservatively without taking special treatment measures. Six months after LC, the umbilical induration pain affected her quality of life, and the patient requested surgical resection. Preoperative ultrasonography and abdominal computerized tomography (CT) revealed nodular changes around the umbilicus and no abdominal mass. Local resection of the periumbilical mass was performed, and the pathological confirmation was invasive adenocarcinoma. Subsequently, the patient underwent repeat periumbilical mass enlargement resection. Postoperative pathology showed no cancer at the enlarged resection margin, yet the umbilical center pathology showed invasive adenocarcinoma. The excised pathology was sent to the Sun Yat-sen University Cancer Center for consultation because of the rare nature of the findings associated with the case. After consultation, a diagnosis of umbilical urachus adenocarcinoma was confirmed based on pathological morphology, immunohistochemistry, and the specific anatomical location of the tumor. This case report shown that when there is a persistent mass induration in the navel after LC surgery, the possibility of incision tumor should be considered, rather than simply excluding the possibility of a cancer based on a non-cancer medical history.