Case Report: Pseudoprogression of pancreatic acinar cell carcinoma after PD-1 blockade integrated treatment

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.