Background/Aims: Adenosquamous carcinoma of the gallbladder is relatively rare. Its biological behavior and optimal surgical procedure are still controversial. Methodology: Clinicopathological factors and proliferating cell nuclear antigen expression were studied in four stage IV adenosquamous carcinoma patients who underwent curative surgery between June 1987 and April 2000, comparing those of 14, stage IV adenocarcinoma patients at the same period. Results: Preoperative radiological evaluation disclosed a mass invading to the adjacent organs in all cases (liver in 3 cases, and liver and stomach in one case). Three patients (case 1, 2 and 3: well-differentiated adenosquamous carcinomas) were all alive without recurrence in 10, 7, and 2 years after surgery. In contrast, the remaining patient (case 4: moderately differentiated adenosquamous carcinoma) with positive pathologic factors (lymph node metastasis, vascular invasion, etc) deceased one year after surgery due to peritoneal dissemination. When survival rate of adenosquamous carcinoma was compared, the prognosis of adenosquamous carcinoma was significantly better than that of adenocarcinoma (P=0.0103). Comparison of pathological factors revealed that the frequency of lymph node metastasis was significantly higher in adenocarcinoma than in adenosquamous carcinoma (P=0.004). Consistent with these findings,- the positivity rate of proliferating cell nuclear antigen labeling was significantly lower in squamous carcinoma component, compared with adenosquamous component (P<0.0001) or adenocarcinoma (P<0.0001). Conclusions: Even in patients with stage IV adenosquamous carcinoma of the gallbladder, a long-term survival may be obtained by curative surgery if the squamous component is predominant.
