Background: An inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor, sometimes with urinary bladder involvement (though this is extremely uncommon). Due to its rarity, the exact etiology and optimal treatment strategy remain unclear. Methods: A review of the existing literature on IMT of the urinary bladder was performed. Results: We report a case of a 32-year-old female presenting with frequent urination, hematuria with clots, and lower abdominal pain for one month. Initially misdiagnosed as acute cystitis, the symptoms persisted despite antibiotic therapy. Laboratory findings revealed severe anemia, and imaging studies identified a large bladder mass. Transurethral resection of the bladder tumor (TURB) was performed, and a 96 g mass was removed. Histopathological examination confirmed IMT of the urinary bladder (IMTUB) with positive immunohistochemical staining for ALK, vimentin, and actin. Follow-up at 30 months showed no recurrence, with annual cystoscopy and CT scans confirming remission. Conclusions: IMTUB should be considered in young patients presenting with hematuria and lower urinary tract symptoms. Early diagnosis through cystoscopy, imaging, and histopathological confirmation is essential for appropriate management. TURB remains the gold standard for treatment, with ALK inhibitors providing additional therapeutic options in select cases. Long-term follow-up is necessary due to the unknown malignant potential of IMTUB.