Recurrent pancreatic acinar cell carcinoma following a 7-year disease-free interval: A case report and literature review

Introduction and importance: Pancreatic acinar cell carcinoma (PACC) is a rare malignant pancreatic tumor, accounting for only 1% of all pancreatic neoplasms. It has distinctive clinical, radiological, and histological features. Case presentation: Here, we report a case of PACC diagnosed 7 years after surgical treatment for pancreatic ductal adenocarcinoma (PDAC). The recurrence was suspected during routine follow-up via abdominal computed tomography scan, which showed a local mass without biliary ducts dilation, vascular involvement, or any specific radiological signs. However, clinical examination and laboratory workup, including tumor markers (CA 19-9 and carcinoembryonic antigen), were normal. By comparing samples obtained via endoscopic ultrasound fine-needle aspiration of the pancreatic mass to the histopathological findings of the prior duodenopancreatectomy, a diagnosis of local recurrence of previously misdiagnosed PACC was established. Clinical discussion: PACC is a rare pancreatic epithelial malignancy (1%), for which radical surgical resection remains the treatment of choice. However, it is usually diagnosed at an advanced stage (with metastasis). The most common differential diagnoses include pancreatic adenocarcinoma, pancreatic neuroendocrine tumors, solid pseudopapillary neoplasms, and pancreatoblastoma in the pediatric population. Histopathological examination combined with immunohistochemical staining remains the cornerstone for establishing the diagnosis. In our case, ultrasound-guided fine needle aspiration of the pancreatic mass, compared to the previous duodenopancreatectomy, led to the diagnosis of a local recurrence of a previously misdiagnosed initially as PDAC, with the longest survival (84 months) ever described in the literature. Conclusions: Due to its rarity, PACC remains a diagnostic challenge. It has a better prognosis than PDAC; radical resection is recommended.