Inflammatory Myofibroblastic Tumor of the Urinary Bladder: A Case Report.

Aggressive large tumors of the bladder are not always malignant or invasive. Inflammatory myofibroblastic tumor (IMT) of the bladder, a typically benign lesion, is challenging to diagnose as it presents similarly to other malignant disease processes. Awareness of the specific pathological features of these rare tumors is necessary to promote accurate diagnosis and avoid unnecessary treatment. We discuss a case of a 51-year-old Caucasian man who presented with gross hematuria. Cystoscopy demonstrated a large, sessile bladder mass concerning for bladder cancer. After an aggressive transurethral resection of this mass, pathology demonstrated an IMT. Lesions of this nature are extremely rare in the bladder and present similarly to an invasive bladder tumor. IMT is a rare typically benign tumor in the urinary bladder with a presentation concerning for malignant disease. Transurethral resection of the tumor is the standard for diagnosis; however, immunohistochemistry can be useful in distinguishing IMT from other spindle cell malignancies. After initial treatment with transurethral resection, patients have an ∼1.6% chance of lesion recurrence within 6 months. Given these findings, treatment with transurethral resection of bladder tumor in combination with routine cystoscopy and CT urogram every 3 to 6 months is adequate and reasonable for monitoring for local recurrences in the majority of cases.