AIM: To determine if cholecystectomy and liver’s round ligament removal is a necessary step during cytoreductive surgery (CRS) and HIPEC. METHODS: This was a retrospective observational study based on records from 180 patients treated in our center from 2005 to 2014. All patients have been offered CRS and HIPEC for peritoneal pseudomixoma (20 patients), peritoneal mesothelioma (7 patients), peritoneal carcinomatosis from ovarian cancer (66 patients), colorectal cancer (42 patients), gastric cancer (10 patients), mucinous adenocarcinoma of the appendix (28), and other abdominal malignancies (7 patients). We performed a cholecystectomy and we removed the round ligament of the liver in all patients, even if there wasn’t a macroscopic tumor infiltration of the above anatomical structures. We reviewed the histological reports of all 180 patients. RESULTS: Patients with peritoneal carcinomatosis from mucinous adenocarcinoma of the appendix were treated more aggressively, due to the macroscopic appearance of the disease. Histologic report show no evidence of metastases at the round ligament of the liver in 21, 4% of the patients that were treated with CRS although it was estimated to be involved based on the macroscopic examination at the time of surgery. Tumor involvement of the gallbladder was overestimated, macroscopically, at the same patients in 25% of the cases. In patients with peritoneal carcinomatosis from ovarian cancer, macroscopic appearance of the gallbladder may be delusive. In 25% of the above patients there was a microscopic tumor involvement of the gallbladder, although there was not macroscopic evidence of the disease. CONCLUSION: More extended cytoreductive surgery is needed in case of peritoneal carcinimatosis from ovarian cancer. In case of PC from mucinous adenocarcinoma of the appendix, it’s difficult to calculate the extent of the disease and avoid unnecessary surgical excisions. More data is needed to confirm the above.