The authors report an unusual presentation of inflammatory pseudotumor (IPT) that caused intestinal obstruction in a 9-year-old boy, and discuss the clinicopathologic features of this rare entity with emphasis on diagnosis and treatment. There are no specific presumptive clinical and laboratory findings, including tumor markers and imaging techniques, that distinguish mesenteric IPT from other abdominal mass lesions. The most important diagnostic aid is to bear this entity in mind when a child presents with intestinal obstruction associated with an abdominal mass. Radical unnecessary surgical procedures or potentially harmful therapy should be avoided, and appropriate treatment is achieved by total excision of the lesion in most of the cases. J Pediatr Surg 33:1843-1845. Copyright (C) 1998 by W.B. Saunders Company.