Inflammatory pseudotumors present clinically as mass lesions and micro
scopically show a spectrum of nonspecific inflammatory and regenerativ
e changes, When the mesentery or retroperitoneum are involved, differe
ntiation from inflammatory fibrosarcoma poses a diagnostic problem. Th
e authors report on a 7-year-old boy who presented with fever, anemia,
weight loss, and a retroperitoneal mass. Needle biopsy results of the
mass showed features consistent with inflammatory pseudotumor. Examin
ation of the resected mass showed actinomycosis. Copyright (C) 1997 by
W.B. Saunders Company.