Autoimmune pancreatitis and concurrent small lymphocytic lymphoma: not just a coincidence?

CASE: A 76-year-old gentleman presented with painless jaundice, weight loss, and anorexia. Computed tomography imaging revealed fullness of the pancreatic head and multiple enlarged retroperitoneal lymph nodes. Cholangiogram revealed a distal common bile duct stricture. Due to concerns of malignancy, the patient underwent operative exploration. Several enlarged lymph nodes in the aortocaval region and a firm hard mass in the pancreatic head were found. Frozen section from one of the lymph nodes was suspicious for low-grade lymphoma. A pancreaticoduodenectomy was performed. Histologic analysis of the pancreatic head revealed a lymphoplasmacytic infiltrate with stromal fibrosis consistent with autoimmune pancreatitis. The retroperitoneal lymph nodes were involved by small lymphocytic lymphoma.

DISCUSSION: Autoimmune pancreatitis is the most common benign diagnosis after pancreatic resection for presumed malignancy. It has a well-documented association with autoimmune conditions, such as Sjögren's syndrome, inflammatory bowel disease, and sclerosing cholangitis. Additionally, chronic lymphocytic leukemia-small lymphocytic lymphoma is often associated with autoimmune phenomena, most notably autoimmune hemolytic anemia. However, an association between autoimmune pancreatitis and small lymphocytic lymphoma has not been previously described. To our knowledge, this is the first reported case of a patient with concurrent autoimmune pancreatitis and small lymphocytic lymphoma.