Inflammatory myofibroblastic tumor presenting as acute abdomen: report of one case.

Inflammatory myofibroblastic tumor (IMT) is a very rare benign tumor composed of myofibroblastic spindle cells of uncertain etiology, which can occur at any age and affect any organ system. More and more cases of IMT in children have been described in pediatric literature in recent years. However, this tumor occurring intraabdominally in children has rarely been reported in Taiwan. Here we present a 1-year-9-month-old boy who had fever and abdominal pain only for 2 days, symptoms mimicking acute abdomen. After imaging study, a huge tumor nearly 10 cm in diameter was incidentally found over the right abdomen with unknown origin and nature. After surgical removal of the tumor, IMT was confirmed by the pathological findings. It is very difficult to make an accurate preoperative diagnosis on this tumor according to past experience, so the role of pathological diagnosis with immunohistochemical study becomes important. This case illustrates that IMT should be considered as a possible cause of intra-abdominal mass in children who have fever of unknown origin.