A case of multicentric pancreatic mixed acinar-ductal carcinoma diagnosed by a yogurt-like cell clump flowing from the papilla of Vater

BACKGROUND: Histological confirmation is needed when the pancreatic lesions is uncertain for neoplastic or nonneoplastic. Current case with multicentric pancreatic carcinomas showing indefinite clinical images was successfully diagnosed by a biopsy of a novel object expelled from the papilla. CASE PRESENTATION: A 71-year-old male was referred because of elevated serum pancreatic enzymes. Computed tomography revealed an unclear low-density area in the pancreatic body without evidence of tumor and mild dilation of the upstream main pancreatic duct (MPD). Other images, including abdominal ultrasound, endoscopic ultrasound, and magnetic resonance imaging, did not demonstrate cancerous findings. Endoscopic retrograde cholangiopancreatography showed a crab-claw-like obstruction in the MPD. Surprisingly, the component constituting the obstruction was moved by contrast injection and spilled out of the papilla orifice as a yogurt-like white object. Biopsy of this object by histology revealed a cancer cell clump. Pancreatectomy was performed, and pathology of the resected pancreas showed multiple nodular tumors replacing the acini and extending into the MPD. These neoplasms histologically resembled mixed acinar-ductal carcinoma. CONCLUSION: Current report presented a rare tumor with multicentric pancreatic lesions, preoperatively diagnosed by a biopsy of an uncommon substance.