Evaluation of cystic lesions of the pancreas based on clinicopathologic parameters

Abstract

Aims: To identify demographic, histopathologic and immunohistochentical features of pancreatic cystic lesions, which could assist diagnosis of neoplastic ones.Materials and methods: Sixty-seven cystic lesions from pancreatic resections between 2001 and 2013 were studied. Patient demographics and cyst location and size were recorded. Forty-sir specimens with adjacent non-lesional parenchyma were evaluated for pancreatic intraepithelial neoplasia (PanIN). Neoplastic cysts were immunohistochemically tested for ki67, p53, and progesterone receptor. Ten high-power fields were examined to determine ki67 proliferative index (PI; average percentage of nuclear staining) and p53 status (<1% stained nuclei indicating negative). Presence/absence of progesterone receptor (PR)-positive nuclei in pericystic stromal cells Was recorded.Results: Eighteen (26.9%) of the 67 lesions were non-neoplastic and 49 (73.1%) were neoplastic. Serous cystadenomas (SCAs) were most common (n=23: 34.3%), and 59 (88%) of the patients were women. Mean ages for the mucinous cystic neoplasm (MCN) and SCA subgroups were 46.7 and 64.6 years, respectively, and these lesions tended to be in the pancreatic tail and head, respectively. ki67 PI was higher for non-invasive MCNs with high-grade dysplasia than low-grade dysplasia (20% vs. 4-6%, respectively). No neoplasms were p53-positive. Only MCNs were PR-positive. SCA was the lesion most frequently associated with PanIN.Conclusion: Age of patient and the location of cyst are distinctive features in neoplastic pancreatic cysts. Diameter of the cyst gives an idea about the malignancy potential of the lesions. In MCNs. considering the increased risk of multiple foci of varying degrees of dysplasia, ki67 proliferative index is useful as well as the adequate sampling of the cyst for the accurate diagnosis of these foci, particularly when the presence or degree of it cannot he adequately assessed in hematoxylin and eosin (HE)-stained sections.