Functional pancreatic acinar cell carcinoma extending into the main pancreatic duct and splenic vein.

INTRODUCTION: Pancreatic acinar cell carcinoma (ACC) has several unique characteristics, such as its progression pattern, spreading into the pancreatic duct and large blood vessels, and its secretion of pancreatic exocrine enzymes, which induces a paraneoplastic syndrome. CASE REPORT: A 79-year-old Japanese man, with medical history of chronic renal failure, was referred to our institution for the examination of his abdominal pain and hyperglycemia. Plain computed tomography demonstrated a mass lesion, 4 cm in diameter, in the body of pancreas. Abdominal ultrasonogram demonstrated a bulky, hypoechoic mass extending into the splenic vein. Multiple hepatic nodules were detected on suspicion of metastasis. Positron emission tomography using 18F-fluorodeoxyglucoase revealed the tumor extended towards the pancreatic head through the main pancreatic duct. We obtained the tumor tissues from the pancreatic body using endoscopic ultrasound-guided fine-needle aspiration biopsy. Pathological diagnosis, supported by immunohistochemistry, was that of an ACC. In the follow-up period, he complained of subcutaneous nodules and arthralgia on his lower legs. Serum and intra-articular lipase levels were elevated, 6,420 I/U and 594 I/U, respectively. Histology of the skin lesion at the knee joint showed necrotizing panniculitis with eosinophilic infiltration. The patient was treated with weekly gemcitabine, but succumbed to acute respiratory distress unexpectedly 2 months after the initial diagnosis.