Isolated lymphoplasmacytic sclerosing pancreatitis involving the pancreatic tail

We present an interesting case of a 62-year-old woman with a 3-month history of vague, left-sided abdominal pain. CT imaging revealed a hypodense lesion in the tail of the pancreas. The patient had no history of pancreatitis or autoimmune diseases. Laboratory testing revealed a normal CA19-9 (33 U/mL) and an elevated IgG4 (133 mg/dL). Due to concerns of pancreatic malignancy, she underwent operation. We found a dense, inflammatory mass in the tail of the pancreas, which was removed via an open distal pancreatectomy with splenectomy. Histologic analysis revealed a pancreas with sclerotic ducts and surrounding lymphoplasmacytic inflammation most consistent with lymphoplasmacytic sclerosing pancreatitis (LPSP). LPSP, also termed autoimmune pancreatitis, is a benign disease of the pancreas, which can mimic pancreatic adenocarcinoma. It is the most common benign finding diagnosed on pathology after pancreatic resection for presumed malignancy. LPSP most commonly involves the head and, more uncommonly, the tail of the pancreas. It can be successfully treated with steroids obviating the need for resection. IgG4 levels may assist in recognition of this disease. As our experience with utilization of IgG4 testing and knowledge of the systemic nature of LPSP increase, patients with this disease may be spared unnecessary resection.