Case Report: Pseudoprogression of Pancreatic Acinar Cell Carcinoma after PD-1 Blockade Integrated Treatment

Xinyuan Bai^1,2Di Yang^1,3Jingjing Chen^1,2Yaru Liu^1,2Haochen Tang^1,3Xiang Kong^1,4Baorui Liu^1*Huizi Sha^1*Juan Du^1,2,3,4*

• ¹Department of Oncology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University & Clinical Cancer Institute of Nanjing University, Nanjing, China
• ²Clinical College of Nanjing Drum Tower Hospital, Nanjing University of Chinese Medicine, Nanjing, China
• ³The Comprehensive Cancer Center, Nanjing Drum Tower Hospital, Clinical College of Nanjing Medical University, Nanjing, China
• ⁴Drum Tower Clinical Medical College of Jiangsu University, Zhenjiang, China

Pancreatic Acinar Cell Carcinoma (PACC) is a rare subtype of pancreatic cancer, and its systematic treatment protocol is still pending for further exploration. There have been a few reports that PACC patients benefited from immunotherapy-integrated treatment. Here, we present a metastatic PACC patient who had new hepatic lesions but lowered serum AFP and CA19-9 after 2 cycles of integrated treatment that included chemotherapy, PD-1 blockade and antiangiogenic therapy, which was later confirmed to be pseudoprogression (PsP) by pathological diagnosis. So far as we know, this is the first reported PsP case of PACC. This case highlighted the value of biopsy in distinguishing PsP from authentic tumor progression of PACC.