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Pediatr Radiol (1986) 16:210-215

Pediatric Radiology 9 Springer-Verlag 1986

Inflammatory pseudotumor of the mesentery and small intestine D. L. Day 1, S. Sane 3 and L. P. Dehner 2 Departments of 1Radiology, and ZLaboratory Medicine and Pathology (Division of Surgical Pathology), University of Minnesota Medical School and Hospitals, and 3Department of Radiology, Minneapolis Children's Health Center and Hospital, Minneapolis, Minnesota, USA

Abstract. Three cases of abdominal inflammatory pseudotumor or inflammatory myofibroblastic tumor of the small intestinal mesentery are presented with additional examples from the literature. An abdominal mass was detected in three preadolescent children who presented with fever, growth failure, hypochromic anemia, thrombocytosis and polyclonal hypergammaglobulinemia. The radiographic findings confirmed the presence of a mass. Following surgical resection, the systemic manifestations dramatically resolved. The solid mesenteric mass was composed of spindle cells with the features of myofibroblasts and mature plasma cells and small lymphocytes. Clinical follow-up confirmed the benign nature of this lesion with no signs of recurrence in any patient from 3 to 6 years after the initial surgery.

An abdominal and/or pelvic mass in a child or adolescent is a cause for considerable concern when first detected and before a pathologic diagnosis can be

established. During infancy, multicystic dysplastic kidney and congenital hydronephrosis are the two principal causes for an abdominal mass whereas later in childhood, neuroblastoma, Wilms' tumor and malignant lymphoma are the more common conditions. The occasional ovarian cyst or teratoma, hepatic neoplasm (hemangioendothelioma or hepatoblastoma), rhabdomyosarcoma and lymphangioma almost complete the list of causes of abdominal masses in children. We would like to report our experience with three cases of a tumor-like lesion of the small bowel mesentery, which has been variously designated as an inflammatory pseudotumor or plasma cell granuloma in the lung and other sites [1, 2]. There are many unresolved questions about the basic nature of this tumefactive process since it is unclear at this point whether it represents a true neoplasm or an exuberant inflammatory reaction whose pathologic features simulate a neoplastic proliferation. Because of its rather characteristic clinical presentation, the diagnosis should be strongly suspected pre-operatively once the clinician and radiologist are aware of its existence.

Fig. l a and b. (Case 1) a Transverse pelvic CT scan demonstrates midline, homogeneous, noncalcified, 9 cm soft tissue mass displacing normal structures posteriorly and laterally. Note the isolated distal ileum superior to the mass (arrow). b Transverse pelvic ultrasound of 9 cm lobulated mass shows mixed echo pattern, but predominantly solid. Mulitple small, non-echoic areas represent areas of necrosis or small vascular lakes. (S, septum; V, vascular lacunea)