An autopsy case of multiple liver metastases from minute pancreatic acinar cell carcinoma clinically diagnosed as primary hepatic acinar cell carcinoma.

Acinar cell carcinoma of the pancreas is a rare malignancy characterized by lipase secretion and a high propensity for distant metastases, most commonly to the liver. Although primary hepatic acinar cell carcinoma has been reported, its existence remains controversial due to limited pathological confirmation. We report the case of a 66-year-old male who presented with sudden right upper quadrant pain and elevated serum lipase. Imaging revealed multiple hepatic tumors, with no evidence of a primary tumor in the pancreas. Histopathological examination of a liver biopsy confirmed acinar cell carcinoma. On this basis, the patient was clinically diagnosed with primary hepatic acinar cell carcinoma in the absence of radiological evidence of pancreatic disease. However, autopsy revealed a 5-mm acinar cell carcinoma in the pancreatic head. Additionally, an incidental intraductal papillary mucinous carcinoma was identified in the pancreatic tail. This case demonstrates that even minute pancreatic acinar cell carcinomas can result in extensive hepatic metastases and may be misdiagnosed as primary hepatic acinar cell carcinoma. Furthermore, the coexistence of acinar cell carcinoma with intraductal papillary mucinous carcinoma represents a novel finding. These observations underscore the importance of autopsy and comprehensive pathological evaluation in establishing accurate diagnoses of rare pancreatic neoplasms.