We report a case of a 64-year-old woman with anaplastic carcinoma of the pancreas(ACP) with cyst formation and review 60 ACP cases reported in Japan. In 20% of cases, laboratory tests revealed severe anemia(hemoglobin level < 10.0 g/d L) and elevated leucocyte counts(> 12000/mm3), which were likely attributable to rapid tumor growth, intratumoral hemorrhage, and necrosis. Elevated serum CA19-9 levels were observed in 55% of cases. Cyst-like structures were observed on imaging in 47% of cases, and this finding appears to reflect subsequent cystic degeneration in the lesion. Macroscopically, hemorrhagic necrosis was observed in 77% of cases, and cyst formation was observed in 33% of cases. ACP should be considered when diagnosing pancreatic tumors with a cyst-like appearance, especially in the presence of severe anemia, elevated leucocyte counts, or elevated serum CA19-9 levels. We report a case of a 64-year-old woman with anaplastic carcinoma of the pancreas (ACP) with cyst formation and review 60 ACP cases reported in Japan. In 20% of cases, laboratory tests showed severe anemia (hemoglobin level <10.0 g / dL) and elevated leucocyte counts (> 12000 / mm3), which were likely attributable to rapid tumor growth, intratumoral hemorrhage, and necrosis. Elevated serum CA19-9 levels were observed in 55% of cases. on imaging in 47% of cases, and this finding appears to reflect subsequent cystic degeneration in the lesion. Macroscopically, hemorrhagic necrosis was observed in 77% of cases, and cyst formation was observed in 33% of cases. pancreatic tumors with a cyst-like appearance, especially in the presence of severe anemia, elevated leucocyte counts, or elevated serum CA19-9 levels.