陳鵬¹、張延驊^1,2、黃志賢^1,2 

¹臺北榮民總醫院 泌尿部； 

²國立陽明大學醫學院泌尿學科及書田泌尿科學研究中心 

Peng Chen¹, Yen-Hwa Chang^1,2, William J. Huang^1,2 

¹ Department of Urology, Taipei Veterans General Hospital; 

² Department of Urology, School of Medicine and Shu-Tien Urological Institute, 

National Yang-Ming University, Taipei, Taiwan 

 

Inflammatory myofibroblastic tumor (IMT) is a rare tumor with unknown malignant potential. It’s also called inflammatory fibrosarcoma, inflammatory pseudotumor, plasma cell granuloma in different report. It consists of myofibroblasts with plasma cells, lymphocytes and eosinophils, the standard of treatment and follow-up protocol is yet to be established. Herein, we report a case of IMT of urinary bladder in a young female.

A 22-year-old female graduate student who denied systemic diseases and prior operation history before presented with abnormal menstruation for three months. At first, she visited Gynecology out-patient clinic, and incidental finding of bladder mass lesion with severe left hydronephrosis was noted by sonography. She then received abdominal computed tomography scan (CT), which revealed a huge heterogeneous enhancing tumor at bladder base with left ureterovesical junction obstruction and resultant marked left hydroureteronephrosis and thin parenchyma. She undergone transurethral resection of bladder tumor (TURBT) in January 2019 at first hospital and the pathology disclosed inflammatory myofibroblastic tumor of bladder. Left percutaneous nephrostomy was done for relief of hydroureteronephrosis. Gross hematuria was noted in late January 2019, and she went another hospital for second opinion where urine cytology showed negative finding of urothelial carcinoma. She received transcatheter arterial embolization for the tumor (TAE) in February 2019. However, hematuria recurred after TAE, she then went to the our hospital for further evaluation and management. All blood tests including renal function were normal, except hemoglobin (7.2 g/dl). She subsequently underwent palliative TURBT with resected tumor weight of 300 gm from left posterior wall and non-visualization of left ureteral orifice. Histopathologically, the stromal tumor composed of loose spindle cell lesions with lymphoplasmacytic infiltration in a myxoid background. These spindle cells are immunoreactive for ALK, which is compatible with the diagnosis of IMT. Following the suggestion of multidisciplinary tumor board discussion, she subsequently received crizotinib therapy since March 2019. Regression of hydronephrosis was found in follow-up CT scan but antegrade pyelography showed persistent left ureterovesical junction obstruction, and antegrade double J stent insertion failed. Thus, she received left radical nephroureterectomy and second look TURBT in May 2019. Residual IMT was found in urinary bladder tumor base. Oral crizotinib therapy was continued for another 6 months. To date, she was regularly followed up with CT scan with no evidence of recurrence.

The clinical reported cases of bladder IMT was scarce based on literature review, and extremely rare in Asian population. TURBT is the mainstay surgical intervention with low rate of recurrence. Aside from cystoscopic surveillance, CT scan was also required. As for systemic therapy, since ALK rearrangement was observed in most of IMT patients, the use of ALK inhibitor may be considered in both neoadjuvant and/or adjuvant settings.