The role of ultrasound in the differential diagnosis of serous and mucinous cystic tumours of the pancreas.

OBJECTIVE: To evaluate the usefulness of a series of ultrasound parameters in the differential diagnosis between serous and mucinous forms of cystic tumours of the pancreas.

SETTING: Retrospective comparative study between the histological analysis of surgical specimens from cystic tumours of the pancreas (4 serous cystadenomas, 6 mucinous cystadenomas and 11 mucinous cystadenocarcinomas) and ultrasound evaluation.

METHODS: The ultrasound images of the 21 tumours were analysed by an operator who did not know the result of the histological diagnosis and were divided according to Johnson's criteria (number of cysts > 6 and diameter < 2 cm for serous tumours; number of cysts <6 and diameter >2cm for mucinous tumours) and according to other anatomicopathological parameters such as the presence of septae, endocystic projections, central scar, central calcification and/or in the tumour wall.

RESULTS: The ultrasound study gave a correct diagnosis in two out of the four (50%) serous cystic tumours. A central scar and internal calcification was present in one of them. Fifteen (88.2%) of the 17 mucinous tumours were correctly diagnosed; one presented peripheral calcifications and three endocystic projections.

CONCLUSION: Ultrasound has a high degree of sensitivity in the differential diagnosis of serous and mucinous cystic tumours of the pancreas if the ultrasound aspects corresponding to the anatomicopathological structure of the neoplasms are correctly evaluated.