BACKGROUND: Pancreatic acinar cell carcinoma (PACC) is a rare subtype of pancreatic cancer, and its clinicopathological behavior is not fully understood because of its rarity. The excision of the tumor is the best treatment, but PACC patients often have distant metastasis at the time of first diagnosis and sometimes have relapse after surgery. Thus, appropriate anti-tumor agents need to be administered
however, there is still no standard chemotherapy regimen for PACC. We report a case of PACC in a patient with breast cancer susceptibility gene ( CASE DESCRIPTION: A 67-year-old man was treated for breast cancer in 2016. In 2022, he experienced a continuous left back pain, and abdominal computed tomography (CT) revealed a 47-mm hypo-dense mass in the pancreatic tail and a 100-mm slightly enhanced mass in the liver at segment 8. He was diagnosed with PACC with liver metastasis by liver and pancreatic tumor biopsies. He was started on mFFX and, at the same time, we performed an analysis of the CONCLUSIONS: mFFX might be prioritized as the first-line chemotherapy for PACC patients, and an analysis of the