Characterization of Cystic Lesions of Pancreas by Computed Tomography Scan- A Retrospective Study

BACKGROUND Cystic lesions of the pancreas consist of both neoplastic and non-neoplastic lesions. Computed tomography (CT) scan is commonly used in imaging cystic lesions of pancreas as it is easily available and less time consuming. In this study, we evaluate the different characteristic features of cystic lesions of pancreas and differentiate them based on imaging. METHODS This is a retrospective study done over a period of 5 years. 94 patients with cystic lesions of pancreas were selected and analysed. All patients had proven final diagnosis by surgery, by endoscopy guided aspiration or by follow up. Various parameters of the cysts were studied like the age and sex distribution, incidence, size of the lesion, location, thickness of septations, nature of calcification, pancreatic duct dilatation if any, size of the largest cyst within the lesion, approximate number of cysts, presence of any solid component, nature of enhancement, presence of the wall and contour of the lesion. Descriptive statistics like percentage was used and each cyst was differentiated based on the above features. RESULTS Overall, pseudocysts were the commonest cysts, and all were associated with pancreatitis. They were commonly seen in the middle-aged males. Serous cystadenomas were the commonest neoplastic cysts. Benign neoplastic cysts were common in females and malignant neoplastic cysts were common in males. Serous cystadenomas were common in head of the pancreas whereas mucinous cystadenomas were common in tail of the pancreas. All solid pseudo papillary epithelial neoplasm (SPEN) were seen in the tail of the pancreas. No difference in each cyst based on overall size was seen. Mucinous cystadenomas showed fewer but bigger cysts within the lesion compared to serous cystadenomas. Peripheral wall calcification was seen in mucinous cystadenomas whereas central calcifications were seen in serous cystadenomas. Communication with a dilated pancreatic duct and bulging papillae was seen in intraductal papillary mucinous tumour (IPMT). Most of IPMT and serous cystadenomas showed a lobulated invisible wall whereas mucinous cystadenomas showed a smooth visible wall. All malignant cysts were associated with solid component and thick septations. CONCLUSIONS CT scans helps us to diagnose various cystic lesions of pancreas based on different characteristic imaging features.