Mucin Staining of Fine Needle Aspirates from the Cystic Neoplasms of the Pancreas

Ryu, Ji Kon; Seog, Woong Il; Jang, Yoo Hyun; Lee, Woo Jin; Kim, Yong Tae; Park, In Ae; Kim, Sun Whe; Yoon, Yong Bum

Abstract

BACKGROUND/AIMS
Serous cystadenoma (SCA) and mucinous cystic neoplasm (MCN) are common cystic tumors of the pancreas. Most of SCAs are benign but many of MCNs are malignant. Thus, it is very important to differentiate SCA from MCN of the pancreas. The purpose of this study was to examine whether mucin staining of fine needle aspirate (FNA) could differentiate MCN from other cystic lesions.
METHODS
Eighteen FNAs were obtained from 7 MCNs, 4 SCAs, 2 solid and papillary epithelial neoplasms (SPENs), 1 cystic adenocarcinoma and 4 pseudocysts. Cytologic analysis and mucicarmine staining were performed to find out whether mucin was contained in the cytoplasm of the cells or in the background fluid material aspirated from the cysts. RESULTS: Epithelial cells were observed in 11 (79%) from 14 cystic tumors. However, the definite morphological characterization of cystic neoplasms was possible in only 4 MCNs. No mucicarmine positive cells were found in FNAs from cystic neoplasms. On the contrary, background fluid material was stained positively with mucicarmine in 6 (86%) of 7 MCNs and in 1 of 1 cystic adenocarcinoma, but not in cases of SCAs, SPENs, and pseudocysts. CONCLUSIONS: Mucin staining of FNA from cystic tumor of the pancreas, especially for background fluid material, is very useful in the differential diagnosis between MCN and other cystic tumors such as serous cystadenoma.