The surgeon’s diagnosis of incidental carcinoma of the gallbladder intraoperatively is rare (0.1 %), especially when the procedure is performed laparoscopically. In a retrospective review of 3,050 patients undergoing laparoscopic cholecystectomy for cholelithiasis, carcinoma of the gallbladder was discovered during or after laparoscopic cholecystectomy in 10 patients. Interestingly, laparoscopy was converted to an open procedure in only three patients after pathologic diagnosis was confirmed using frozen section [6]. If signs of malignancy are encountered during laparoscopic cholecystectomy, the surgeon should convert to an open procedure [3, 6]. As noted above, the lack of tactile sensation during laparoscopic cholecystectomy makes intraoperative assessment of malignancy quite difficult. A retrospective review of nearly 300 cases of laparoscopic cholecystectomy in which there was suspicion of gallbladder cancer, and frozen section was performed, the incidence of gallbladder cancer was only 1.3 %.

A thickened, infiltrated, or porcelain gallbladder should raise an index of suspicion for the surgeon. Preoperative imaging demonstrating porcelain gallbladder or polypoid lesions of the gallbladder are indications to examine the gallbladder closely intraoperatively for the possibility of malignancy. Among patients presenting with polypoid lesions of the gallbladder, the incidence of cancer is reported to range from 4 to 18 % [8]. Because of this association, patients with porcelain gallbladders should undergo frozen section examination of the gallbladder upon removal if a tumor is not detected intraoperatively by the surgeon.

If an early malignancy (pT1) is diagnosed intraoperatively, no additional resection is required if there has not been a perforation of the gallbladder. If inadvertent gallbladder perforation occurs during its removal, the peritoneal recurrence rate of gallbladder cancer is likely to be increased. In patients with pT2 (into perimuscular fibers) and beyond, hepatic resection of the gallbladder fossa, segmental hepatic resection, and complete dissection of the lymph nodes along the hepato-duodenal ligament (around the bile ducts, hepatic arteries, and portal vein from the hilus of the liver to behind the duodenum and pancreas) is indicated [6, 8, 9]. There are multiple issues to be considered in this situation such as obtaining operative consent for a much larger and unanticipated procedure, the patient’s existing comorbidities and the skill required by the operating surgeon to perform this more complex procedure. Due to these issues, the operating surgeon should decide whether the better option is to perform an open radical resection or whether to close without attempts of resection. When faced with an unexpectedly malignant gallbladder, it is highly recommended that the operating surgeon obtain additional help from a specialty-trained surgeon if the original surgeon is not trained in the more complex surgery. The patient must then be referred for further oncologic work up and potential operative planning for resection (Fig. 17.1).

Most commonly, incidental gallbladder cancer is diagnosed after histologic examination of the gallbladder by the pathologist postoperatively. In many cases, the patient has already been discharged from the hospital and has expected no further gallbladder treatment (see Fig. 17.2 and its description of what is a typical case). For the pathologist and the surgeon, the site of the malignancy in the gallbladder and the pathologic stage must be carefully determined to counsel the patient on appropriate further therapy. Review of the histology by another experienced pathologist or at a tumor board is critical because some stages of disease do not require further surgical therapy. For example, patients with pT1a tumors do not benefit from additional treatment as their prognosis is good. Additional operative resection in patients with stage pT1a incidental gallbladder cancer did not result in better survival when compared with patients who had the initial cholecystectomy performed without additional treatment. Patients with more advanced stages of disease (pT2 or greater), however, may well benefit from additional treatment such as re-resection [10].