Chronic pancreatitis is a relatively common disease. We encountered two different cases of belatedly demonstrated pancreatic carcinoma featuring underlying chronic pancreatitis. The first case was one that was highly suspected as that of a malignancy based upon imaging study, but unfortunately, it could not be confirmed by intra-operative cytology at that time. Following this, the surgeon elected to perform only conservative bypass surgery for obstructive biliary complication. Peritoneal carcinomatosis was later noted and the patient finally died. The second case, a malignant mucinous neoplasm, was falsely diagnosed as a pseudocyst, based upon the lesion’s sonographic appearance and associated elevated serum amylase levels. After suffering repeated hemoptysis, the patient was found to exhibit lung metastasis and peritoneal seeding. We reviewed some of the literature, including those studies discussing chronic pancreatitis predisposing to a malignant change. These two case analyses illustrate clearly that the diagnosis for such conditions, which is simply based upon imagery or pathological considerations may end up being one of a mistaken malignancy. Some of our suggestions for the treatment of such malignancies as revealed herein include, total pancreatomy for univocal mass lesion, and needle aspiration of lesion-contained tissue for amylase, CA199 and CEA levels for a suspicious cystic pancreatic mass. The first case was one that was highly suspected as that of a malignancy based upon imaging study, but unfortunately, it could not be be confirmed by intra-operative cytology at that time. Following this, the surgeon elected to conservative only bypass bypass surgery for obstructive biliary complication. The second case, a malignant mucinous neoplasm, was falsely diagnosed as a pseudocyst, based upon the lesion’s sonographic appearance and associated elevated serum amylase levels. the patients were found to exhibit lung metastasis and peritoneal seeding. including reviewed the history of chronic pancreatitis predisposing to a malignant change. These two case analyzes illu strate clearly that the diagnosis for such conditions, which is simply based upon imagery or pathological considerations may end up one of a mistaken malignancy. Some of our suggestions for the treatment of such malignancies as reveal intended include, total pancreatomy for univocal mass lesion, and needle aspiration of lesion-contained tissue for amylase, CA199 and CEA levels for a suspicious cystic pancreatic mass.