Prognostic markers in smear preparations for pancreatic endocrine neoplasms: A cytomorphologic study and statistical analysis of 20 potential prognostic features.

Abstract

Background:Papanicolaou Society of Cytopathology guidelines place low- and intermediate-grade pancreatic endocrine tumors into the “neoplastic, other” category whereas high-grade pancreatic endocrine tumors are placed in the “malignant” category. No attempt was made to stratify pancreatic endocrine tumors in the “neoplastic, other” category by likelihood for metastases. Histologically, pancreatic endocrine tumors are divided into well, intermediate, and poorly differentiated examples based on mitotic count and Ki-67 proliferation index (PI). PI has been used in the evaluation of cytologic specimens utilizing cell block material. Unfortunately, cell block material may not always be available for analysis, and little data exists as to cytomorphologic features in smear preparations which might distinguish between low- and intermediate-grade endocrine neoplasms and predict metastases.Methods:We studied 36 cases of Diff-Quik stained smear preparations for 20 morphologic features to determine which best-classified cases into poor and not poor outcome categories. Hierarchical logistic regression analysis was used to determine associations between the morphologic features and outcomes.Results:Absolute agreement between raters ranged from 51% to 97% across the 20 morphologic features. About 12 of the 20 morphologic features showed statistically significant associations with poor outcome. Mitoses, irregular nuclear membranes, and 3-fold variation in nuclear size are the best discriminators between poor and not poor outcomes.Conclusions:A scoring system was developed utilizing mitoses, irregular nuclear membranes, and 3-fold variation in nuclear size to divide smears of pancreatic endocrine tumors into poor and not poor outcome groups. The scoring system achieved 84% accuracy in separating cases into poor and not poor outcomes.