Contributor: Gordon K. Klintworth
Inflammatory myofibroblastic tumor (plasma cell granuloma, myofibroblastoma, pseudosarcomatous myofibroblastic proliferation) is benign tumor composed of proliferating myofibroblasts accompanied by an inflammatory cell infiltrate consisting predominantly of lymphocytes and plasma cells. The tumor, which is one variety of inflammatory pseudotumor, occurs mainly in children and adolescents. It usually arises in soft tissues and the abdomen is the affected most often. A chromosomal rearrangement involving the ALK gene has been detected in some myofibroblastomas.