When is a cyst a tumour? ▸

Conventional wisdom states that 90% of cysts of the pancreas are secondary to pancreatitis and only 10% are neoplastic. In this study, the prevalence of pancreatic cysts was evaluated in patients undergoing axial imaging of the abdomen. Of more than 24 000 magnetic resonance imaging or computed tomography scan reports which were searched, 290 patients (1.2%) had pancreatic cysts. Of these, 168 patients had no documentation of pancreatitis in their medical records, suggesting a prevalence of neoplastic cysts of 0.7%. The authors also assessed growth of cystic tumours by comparing the size of the cysts in those patients who had undergone follow up scans. Of 79 patients who had undergone follow up scans, the cyst had increased in size in 15 (19%), had not changed in size in 47 (59%), and had decreased in size in 17 (22%) patients. The mean interval between scans was 16 months. Neither sex, cyst size, nor cyst location predicted neoplasia but symptomatic patients were more likely to have premalignant or malignant pathology (mainly mucinous lesions). Age …