Inflammatory Myofibroblastic Tumor of the urinary bladder: A case report

Inflammatory Myofibroblastic Tumors represent a rare subset of spindle cell tumors that can occur in the genitourinary tract, most commonly within the bladder. These tumors are proposed to fall in a spectrum of benign inflammatory pseudotumors to true sarcomas. This, along with their rarity makes diagnosis and treatment challenging to clinicians. We present a 51-year-old female diagnosed with IMT of the bladder following a presentation for hematuria. Treatment consisted of transurethral resection of the tumor. This case, and the accompanying review of the literature highlight the need for further research due to lack of clarity for diagnosis and treatment.

Inflammatory myofibroblastic tumor of the urinary bladder: A systematic review of the literature and report of a case

Introduction

Inflammatory myofibroblastic tumors (IMTs) are intermediate-grade lesions that frequently recur and rarely metastasize. There are currently no guidelines on the management of bladder IMTs. This systematic review aims to describe the clinical presentation and compare the management options for bladder IMTs.

Methods

A PubMed/Medline search was conducted, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, using the following Mesh terms: ("inflammatory myofibroblastic") AND ("tumor") OR ("tumor") AND ("bladder") AND ("case report"). A total of 75 case reports were included in the analysis.

Results

The mean age of the patients was 36 years. 65% of the cases initially presented with hematuria. 68% of the tumors stained positive for anaplastic lymphoma kinase, and 20% invaded the muscularis. Patients underwent either transurethral resection of the bladder tumor (TURBT) only (34%), TURBT followed by complementary partial cystectomy (16%), or TURBT followed by radical cystectomy (4%). 36% and 9% of the cases underwent partial and radical cystectomy after the initial diagnosis, respectively. Cystectomies were performed using an open (74%), laparoscopic (14%), robotic-assisted (10%), or unknown (2%) approach. At a mean follow-up of 14 months, the recurrence and metastasis rates were about 9% and 4%, respectively. In addition, we present the case of a 49-year-old woman with a bladder IMT who underwent TURBT followed by laparoscopic partial cystectomy. The patient remains tumor free postoperatively (follow-up period of 12 months).

Conclusion

A complete surgical excision of the bladder IMT is crucial for the optimal management of these cases. Proper differentiation of this tumor from sarcoma or leiomyosarcoma leads to the best outcomes.

Inflammatory Myofibroblastic Tumor of the Urinary Bladder: An 11-Year Retrospective Study From a Single Center

Purpose

To share our experience in the diagnosis and treatment of an inflammatory myofibroblastic tumor of the urinary bladder (IMTUB).

Materials and Methods

A database searches in the pathology archives by using the term “inflammatory myofibroblastic tumor” and” bladder” in our hospital department of pathology from 2010 to 2021. Patient characteristics, clinical features, histopathological results, immunohistochemical staining results, and treatment outcomes were reviewed.

Results

Fourteen cases of IMTUB were retrieved. The mean age was 44.7 ± 18.9 years (range 12–74). Nine (64.3%) of the patients presented with hematuria, followed by seven (50%) with odynuria, five (35.7%) with urgent urination, and one (7.1%) with dysuria. Ten (71.4%) of the patients were treated with partial cystectomy (PC), three (21.4%) with transurethral resection of bladder tumor (TURBT), and one (7.1%) with radical cystectomy (RC). Histopathologically, eight (57.1%) had a compact spindle cell pattern. Anaplastic lymphoma kinase (ALK) staining was positive in six (75%) of 8 cases. During a mean follow-up period of 43.9 ± 38 months (range 3–117), a patient had recurrence within half a month. Then, the patient was treated with further TURBT surgery and had no recurrence within 6 months. Thirteen of the patients had no local recurrence or distant metastasis.

Conclusion

Inflammatory myofibroblastic tumor of the urinary bladder (IMTUB) is clinically rare and has a good prognosis. The disease is mainly treated with surgery to remove the tumor completely. It can easily be misdiagnosed as bladder urothelial carcinoma, leiomyosarcoma, or rhabdomyosarcoma, which may result in overtreatment and poor quality of life of patients.

TERT promoter mutation analysis as a surrogate to morphology and immunohistochemistry in problematic spindle cell lesions of the urinary bladder

AIMS

Pseudosarcomatous myofibroblastic proliferations (PSMPs) of the urinary bladder are diagnostically challenging. Diagnostic difficulties are mainly due to frequent cytokeratin expression, variable ALK expression and worrisome morphological features suggestive of malignancy. Conversely, sarcomatoid urothelial carcinoma (UC) may show bland inflammatory myofibroblastic tumour (IMT)-like morphology. TERT promoter mutations are characteristic events in urothelial cancers, but have not been studied in PSMPs.

METHODS AND RESULTS

We compared histomorphological and immunohistochemical features and TERT promoter status in 16 PSMPs and 18 sarcomatoid UC. In a subset of PSMPs, RNA sequencing was performed. At least focal IMT-like morphology was seen in nine of 17 sarcomatoid UC. Atypical mitoses, differentiated urothelial component and heterologous elements were the most reliable distinguishing histomorphological features of sarcomatoid UC, if present. A panel of immunohistochemistry (IHC) including ALK (clone D5F3), p53 pattern, p63 and GATA3 reliably distinguished PSMP from sarcomatoid UC. GATA3 (P = 0.001) and p53 patterns (mutant versus wild-type; P < 0.001) were differentially expressed between PSMPs and sarcomatoid UC. Diffuse pancytokeratin staining was significantly associated with PSMPs (10 of 13) compared to four of 14 sarcomatoid UCs (P = 0.012). TERT promoter mutations were found in 17 of 18 sarcomatoid UC versus none of 16 PSMPs (P < 0.001). RNA sequencing revealed ALK genetic rearrangements in one of two ALK-positive and one of 10 ALK-negative PSMPs, which revealed a novel FN1/RET gene fusion.

CONCLUSION

Careful histomorphological analysis and differential IHC reliably distinguish the majority of PSMPs and sarcomatoid UC. In equivocal cases, TERT promoter mutation analysis and/or detection of ALK expression/rearrangements are valuable additional diagnostic adjuncts, strongly supporting sarcomatoid UC and PSMP, respectively.

Inflammatory Myofibroblastic Tumor of the Urinary Bladder and Ureter in Children: Experience of a Tertiary Referral Center

PURPOSE

To present the clinicopathological characteristics and outcome of children with bladder and ureteral inflammatory myofibroblastic tumors (IMTs) in our center.

METHODS

We reviewed the medical records of patients with bladder and ureteral IMTs from 2010 to 2018. We recorded patients' demographic data, presentation, hemoglobin level, presence of hydronephrosis, tumor size, treatment, and outcomes.

RESULTS

Eight patients with bladder IMTs and 3 with ureteral IMTs were treated at our center during this period. The mean age was 7.1 years. Four patients presented with anemia at diagnosis with the mean hemoglobin level 84.5 g/L. Among patients with bladder IMTs, 5 were male and 3 were female. The most common symptom was lower urinary symptoms in 6 patients, followed by hematuria in 4 patients. 2 patients had complications of hydronephrosis and hydroureter. Among patients with ureteral IMTs, 2 were male and one was female. The most common symptom was abdominal pain, and 3 patients presented with upper urinary tract dilation. All patients underwent surgery. A total of 81.8% were positive for anaplastic lymphoma kinase. Cytokeratin (CK) expression was present in all patients with bladder IMTs, while it was negative in 2 patients with ureteral IMTs. During mean follow-up of 43.4 months, all patients survived event-free.

CONCLUSION

The presence of hydronephrosis and hydroureter is rare in patients with bladder IMTs. Anemia caused by hematuria should be raised the index of suspicion for IMTs. Children with bladder and ureteral IMTs had excellent prognosis. The expression pattern of CK varied between bladder and ureteral IMTs.

Inflammatory myofibroblastic bladder tumor with divergent behavior in a patient with spinal cord injury

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.

Minimally invasive surgery for inflammatory myofibroblastic tumor of the urinary bladder: Three case reports

RATIONALE

Inflammatory myofibroblastic tumors of the urinary bladder (IMTUB) is exceptionally rare. Currently, no standardized treatment has been established for IMTUBs.

PATIENT CONCERNS

Herein we report three cases presenting with hematuria and anemia. A 25-year-old man experienced painless gross hematuria for 2 days and the hemoglobin level continuously dropped to 88 g/L; a 72-year-old man complaining of gross hematuria for seven days; and a 33-year-old woman presenting with gross hematuria, urgency, and frequency for the duration of 20 days, with a hemoglobin level of 61 g/L.

DIAGNOSIS

Ultrasonography, contrast-enhanced computed tomography (CT) scan and magnetic resonance image (MRI) indicated masses of different sizes on the walls of the urinary bladders. Diagnostic transurethral resection of bladder tumor (TURBT) was performed which revealed the diagnosis of IMTUB.

INTERVENTIONS

In our cases, we removed the tumors completely with a minimally invasive approach. The first patient received TURBT only. The other patients underwent further laparoscopic and robot-assisted laparoscopic partial cystectomy respectively for the incomplete resection of tumor by diagnostic TURBT.

OUTCOMES

Histology of the resected specimen had proliferation of spindle cells with inflammation consistent with IMTUB. Immunohistochemical staining revealed that the tumor cells were positive for anaplastic lymphoma kinase (ALK), Vimentin and Ki-67 (20%-40%), negative for smooth muscle actin (SMA), S-100 and desmin confirming the diagnosis of IMTUB. Follow-up cystoscopy and CT or MRI (mean follow-up period: two years) did not detect any local recurrence or distant metastasis.

LESSONS

Bladder-sparing treatment by TURBT or partial cystectomy remains the main mode of treatment for IMTUB. Laparoscopic and robot-assisted laparoscopic approach is safe and may yield satisfactory oncological and functional results. Regular follow-up protocol is necessary after operation.