Inflammatory pseudotumor of the pancreas

We describe a rare example of inflammatory pseudotumor of the pancreas in a 42-yr-old woman, which developed following chemotherapy for lymphoma of the uterine cervix. The patient had developed fatigue, weight loss, abdominal pain, and anemia; abdominal CT scan showed a large mass in the pancreas. Examination of the resected specimen revealed a fleshy, well-circumscribed, 7-cm mass. Histologically, there was a hypocellular to moderately hypercellular, bland spindle-cell proliferation admixed with a prominent infiltrate of lymphocytes, histiocytes, and plasma cells. The spindle cells were vimentin positive but negative for muscle markers; electron microscopy revealed only fibroblastic cells. DNA analysis revealed a diploid population with low S-phase fraction. The patient was well at 6-mo follow-up. It is important for the pathologist to be aware of the existence of this entity in unusual locations such as the pancreas so as to avoid a mistaken diagnosis of malignancy.