Serous cystic neoplasms of the pancreas: a clinicopathologic and immunohistochemical analysis.

Objective: To clarify whether the various subtypes of serous cystic neoplasms (SCNs) of the pancreas can be distinguished from each other by marker profiles.

Methods: The immunoprofiles of 13 SCNs were defined by using antibodies against cytoskeletal, neuroendocrine, hormone receptor, and mucin markers. In addition, we examined the expression of calrentinin and alpha-inhibin.

Results: SCN included 7 cases of serous microcystic adenomas (SMA), 3 cases of serous oligocystic ill-defined adenomas (SOIA), 1 case of solid serous adenoma (SSA), 1 case of von Hippel-Lindau-associated cystic neoplasm (VHL-CN), and 1 case of serous cystadenocarcinoma (SCC). These neoplasms are histologically similar, but differ in their localization, gross appearance, gender distribution, and biological behavior. The various types of SCNs showed a very similar immunoprofile, characterized by positivity for cytokeratins (100%) and negativity for vimentin and synaptophysin. Other markers that were commonly expressed in the SCNs were alpha-inhibin (85%), MUC1 (69%) and MUC6 (77%).

Conclusion: The results suggest that, despite their biologic differences, the various types of SCNs have the same (or a very similar) cell type and may therefore have a common direction of differentiation. A centroacinar origin is supported by the finding that a number of SCNs share MUC1 and MUC6 expression with pancreatic centroacinar cells. Alpha-inhibin, and MUC6 may be regarded as new markers for this type of pancreatic tumor.