Although relatively few types of pancreatic neoplasms are normally encountered in the clinic, understanding their ultrasonographic findings based on histopathology is important in their differential diagnosis. Pancreatic neoplasms are generally classified as solid or cystic. The solid neoplasms include pancreatic carcinoma, endocrine tumor, Solid-pseudopapillary neoplasm (SPN), adenosquamous carcinoma, anaplastic carcinoma, and acinar cell carcinoma; cystic neoplasms, serous cystic neoplasm (SCN), mucinous cystic neoplasm) (MCN), and intraductal papillary mucinous neoplasm (IPMN). However, differential diagnosis must be carefully carried out when the tumor is solid and presents such cystic features as a solid neoplasm with cystic degeneration with a retention cyst or a pseudocyst. With solid neoplasms, it is sometimes difficult to distinguish among adenosquamous carcinoma, anaplastic carcinoma, acinar cell carcinoma, and endocrine tumor with atypical features. Endocrine tumors in particular often show diverse features resulting from cystic degeneration or tumor thrombus in the main pancreatic duct. With cystic neoplasms, it is important to acknowledge that SCN often consists of both micro and macro cysts, or mainly macro cysts. It is also important to recognize the cyst-in-cyst structure of MCN and the cyst-by-cyst structure of IPMN. Ultrasonographic examinations play a critical role in the differential diagnosis of pancreatic neoplasms.