Mixed pancreatic acinar cell-ductal adenocarcinoma: Complexities in diagnosis and treatment

Abstract

Background: Acinar cell carcinoma of the pancreas (ACC) is a rare malignancy, accounting for approximately 1-2% of all pancreatic cancers. Up to a quarter of ACCs are estimated to contain a significant component of another histology such as neuroendocrine or ductal adenocarcinoma. Prognosis and management remain uncertain for these mixed tumors. Case: A 71-year-old was initially diagnosed with biopsy-proven metastatic pancreatic ACC and treated with FOLFOX. Subsequent biopsy of a progressing metastatic site revealed ductal adenocarcinoma, and liquid biopsy showed a PRKAR1A-RAF1 fusion. The patient had a partial response to FOLFOX and died nine months after initial diagnosis. Discussion: This case highlights a metastatic presentation of mixed pancreatic acinar cell-ductal adenocarcinoma, its reasonable response to treatment with FOLFOX, and overall survival which was driven by the more aggressive ductal component. We also report the presence of a RAF1 rearrangement, which may present a possible therapeutic target in these rare tumors.

Keywords

• Acinar
• Mixed
• Ductal
• FOLFOX
• RAF1