Introduction: An inflammatory myofibroblastic tumor of the bladder is rare. Some urothelial carcinoma with sarcomatoid changes may mimic an inflammatory myofibroblastic tumor.
Case presentation: A 76-year-old man with indwelling urinary catheters because of a spinal cord injury presented with gross hematuria. Transurethral electrocoagulation and a resection were performed. A T2-weighted magnetic resonance imaging showed a tumor and hematoma in the bladder diverticulum that pathologically resembled an inflammatory myofibroblastic tumor. This lesion was then removed en bloc by partial cystectomy. Histology showed a squamous cell carcinoma with sarcomatoid changes. After 4 months, a computed tomography showed the lesion had expanded outside the skin adjacent to the bladder.
Conclusion: Some cases of inflammatory myofibroblastic tumors have a malignant course. Urologists therefore need to be aware of the possibility of rare cases of malignant bladder myofibroblasts.
Keywords: bladder cancer; inflammatory myofibroblastic tumor; sarcomatoid changes; squamous cell carcinoma.
© 2019 The Authors. IJU Case Reports published by John Wiley & Sons Australia, Ltd on behalf of the Japanese Urological Association.