Les cystadénocarcinomes pancréatiques sont-ils des cystadénomes mucineux dégénérés?

Objectives of the studyTo define arguments in agreement or disagreement with the generally accepted theory of transformation from benign mucinous cystadenoma (MC) to malignant cystadenocarcinoma (CC) of the pancreas.MethodsA review of the literature since 1978 was conducted together with a comparative analysis of a multicentre retrospective study of the different mucinous cystic tumours of the pancreas: 150 MC, 79 CC and 55 intraductal papillary mucinous tumours of the pancreas (TIPMP). Multiple epidemiological and clinicopathological data were compared between MC and CC: mean age at diagnosis, sex distribution, association with diabetes or concurrent cancer, tumour location and size, type of pancreatic main duct communication, pancreatic fibrosis and serum CA 19-9 levels. The analysis concerned also histopathological features of resected cystadenocarcinomas (n = 58).ResultsTwo features suggested malignant transformation of mucinous cystadenomas: older mean age at diagnosis of CC and histological characteristics revealing areas of benign-appearing epithelium associated with areas of invasive carcinoma in 55% of cases. Conversely, two statistically significant discordant features were observed: a higher proportion of men (40% for CC vs 13% for MC) and a more frequent location in the head of the pancreas (49% vs 27%). The other differences were not in contradiction with the malignant transformation of MC: associated diabetes mellitus, increasing serum CA 19-9 levels and chromosomal aberrations were more frequent in CC. TIPMP were predominant in men (67%), and more common in the head of the pancreas (67%).ConclusionThe risk of malignant transformation of MC should not be questioned, despite sex distribution and location differences between MC and CC. These differences may be due to inaccurate designation of intraductal mucinous carcinomas as communicating CC or of CC as pancreatic mucinous adenocarcinomas.