Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 58 8 2020 11 10 416 418 EN Mehmet Yildirim Department of General Surgery, Izmir Bozyaka Education and Research Hospital, University of Health Sciences, Izmir, Turkey Asuman Argon Department of Pathology, Izmir Bozyaka Education and Research Hospital, University of Health Sciences, Izmir, Turkey Sedat Tan Department of General Surgery, Izmir Bozyaka Education and Research Hospital, University of Health Sciences, Izmir,Turkey. Ahmet Cekic Department of General Surgery, Izmir Bozyaka Education and Research Hospital, University of Health Sciences, Izmir, Turkey 2020 03 20 2020 05 05 Acinar cystic transformation (ACT) or acinar cell cystadenoma is a rare benign tumor of the pancreas. Their clinical presentation is nonspecific, thus hampering their detection and frequently leading to misdiagnosis. In this report, we present a case of ACT of the pancreas in a 54-year-old man that was vague abdominal symptoms. A magnetic resonance imaging was shown a well-defined cystic mass located in the head of the pancreas, measuring 57×47×23 mm. Our patient was treated by pancreaticoduodenectomy. In the macroscopic examination of the mass, a multicystic lesion was found in cream-colored pancreatic tissue. Histological and immunohistochemical studies examination revealed a cystic mass containing multiple cysts at varying sizes, lined by epithelial cells without atypia and positive staining of CK7, CK8/18, and CK19. A high index of clinical suspicion is required to diagnose this tumor. The surgical approach is to ensure accurate diagnosis and to avoid complications. https://acta.tums.ac.ir/index.php/acta/article/view/8367