Inflammatory Myofibroblastic Pseudotumor

Emma Boylan

Children's Memorial Hospital

Mary Wyers, MD

Children's Memorial Hospital


12 year old female presenting with gross hematuria


inflammatory myofibroblastic pseudotumor, inflammatory myofibroblastic tumor, plasma cell granuloma, urinary bladder, IMT, 1593

Publication Date: 2010-02-17


12 year old female presenting with gross hematuria


Ultrasound (images 1 & 2): mass within the bladder that demonstrates vascularity

CT (images 3 & 4): Enhancing mass within the bladder

CT (Images 5 & 6): 6 weeks following resection of the original lesion, it has recurred and grown significantly


Inflammatory myofibroblastic pseudotumor


Inflammatory myofibroblastic pseudotumors are unusual benign lesions that most commonly affect the visceral organs and soft tissues of children and young adults. Determining benignancy is a significant challenge in definitive diagnosis of IMT since imaging and cytoscopic data are non-specific; lesions may be locally aggressive in imitation of malignancy; and small biopsies may make IMT difficult to distinguish from spindle-cell neoplasms. Clinical context, especially age and anatomical site are important factors in determining a diagnosis of IMT prior to surgery. Resection both allows a definitive pathological diagnosis of IMT and carries an excellent prognosis.

As of 2007 there were fewer than 30 reported cases of IMT of the urinary bladder, which is most common in young women. However, the variety of names for this condition in numerous anatomical sites makes the precise number of occurrences difficult to track. Other names for IMT have included inflammatory pseudotumor, plasma cell granuloma, atypical myofibroblastic tumor, postoperative spindle cell nodule, pseudosarcomatous myofibroblastic proliferation, nodular fascitis, and pseudosarcomatous fibromyxoid tumor. IMT are characterized by three histological patterns which may occur in combination within the same lesion: 1) myxoid/vascular; 2) compact spindle cell; and 3) hypocellular fibrous. The treatment of choice for this condition is conservative surgery, either complete transurethral resection or partial cystectomy.


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