Background and Objectives:Factors that contribute to difficult laparoscopic cholecystectomy (LC) in acute cholecystitis (AC) that would affect the performance of early surgery remain unclear. The purpose of this study was to identify such risk factors.Methods:One hundred fifty-four patients who underwent LC for AC were retrospectively analyzed. The patients were categorized into early surgery and delayed surgery. Factors predicting difficult LC were analyzed for each group. The operation time, bleeding, and cases of difficult laparoscopic surgery (CDLS)/conversion rate were analyzed as an index of difficulty. Analyses of patients in the early group were especially focused on 3 consecutive histopathological phases: edematous cholecystitis (E), necrotizing cholecystitis (N), suppurative/subacute cholecystitis (S).Results:In the early group, the CDLS/conversion rate was highest in necrotizing cholecystitis. Its rate was significantly higher than that of the other 2 histopathological types (N 27.9% vs E and S 7.4%; P = .037). In the delayed-surgery group, a higher white blood cell (WBC) count and older age showed significant correlations with the CDLS/conversion rate (P = .034 and P = .004).Conclusion:In early surgery, histopathologic necrotizing cholecystitis is a risk factor for difficult LC in AC. A higher WBC count and older age are risk factors for delayed surgery.