Numerous small cysts lined by uniform glycogen-rich cuboidal epithelial cells. The intracytoplasmic glycogen is periodic acid-Schiff (PAS) positive and is sensitive to digestion with diastase. Alcian blue stain is negative. The cysts contain proteinaceous fluid which can be useful for distinguishing it from other cystic lesions. Microcystic adenoma has pancreatic and salivary isoenzymes while pseudocysts only contain pancreatic isoenzymes. CEA levels are also low while in mucinous cysts, CEA is high.