Background: The intraductal papillary mucinous neoplasia of the pancreas (IPMN) was first reported 1982 in Japan. IPMNs are primary benign lesions but have an unknown malignant potential. In September 2007 a new score to assess the dignity preoperatively has been published by Fujino et.al. (Am.J.Surg.2007; 194; 304-307). The aim of this study was to evaluate this score using the prospective database of our institution.
Methods: All patients with a pancreatic operation were prospectively analyzed during a three year period (01.01.2004 to 31.12.2006). Patients with a diagnosed IPMN were analyzed by age, sex, surgical procedure, histological findings and preoperative findings of jaundice, diabetes mellitus, patulous papilla, tumor size ≥ 42mm (scored 1 pt); main-duct-type (scored 2 pt); size of pancreatic duct ≥ 6.5mm and Ca 19-9 ≥ 35 U/ml (scored 3 pt). These data were evaluated applying the score by Fujino. Predictive values were estimated by using a cross-tabulation.
Results: Among n = 402 patients receiving a pancreatic operation 17 patients (n = 10 men, n = 7 women) were diagnosed as IPMN. N = 12 had benign lesions and n = 5 carcinomas. Malignant lesions were significantly more frequent in male patients (80%) (p ≤ 0.05). The proportion of benign lesions was balanced. Histologically, the lesions were classified as n = 7 adenomas (41.2%), n = 5 tumors with unknown malignant potential (29.4%) and n = 5 carcinomas (29.4%). The values of the Fujino-Score were 8.4 for carcinomas, 4.0 for IPMN with unknown malignant potential and 4.14 for adenomas (p ≤ 0.05; T-Test). Only 2 lesions were scored from 0 to 1 pt and therefore predicted as benign lesions. Interestingly, the histological findings of these cases were tumors with unknown malignant potential. 10 lesions had score values ≥ 5 pt and so predicted as malign. All patients with carcinomas had a score ≥ 5 pt. N = 2 patients with adenomas were also scored as malign. The IPMN patients with unknown malignant potential were scored in all categories. All patients with carcinomas were scored true positive (sensitivity: 100%), whereas n = 5 benign tumors were scored false positive. 7 patients of 12 patients with benign tumors were scored true negative (specificity: 58%). Taken together the efficiency of the Fujino-Score was 71%.
Conclusion: This analysis of the Fujino-Score showed a high sensitivity of 100% for the identification of carcinomas in IPMN lesions. One drawback might be the high proportion of false positive findings leading to a specificity of only 58%. The IPMN with unknown malignant potential were scored in all categories. Surgical exploration should be considered at a Fujino-Score ≥ 2 points.