Malignant histiocytosis involving pancreas at initial presentation.

A 10-year-old boy with malignant histiocytosis presented with fever, hepatosplenomegaly, and diffuse pancreatic enlargement, mimicking acute pancreatitis. Although malignant histiocytosis involving pancreas at initial presentation is exceptional, this entity should be included in the differential diagnosis of acute pancreatitis, especially when hepatosplenomegaly and pancytopenia are present.