Inflammatory myofibroblastic tumor of the bladder

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 bladder turn malignant: A case report

INTRODUCTION AND IMPORTANCE

Inflammatory myofibroblastic tumor (IMT) of the bladder is a rare sight, which can be distinguished by the proliferation of spindle cells and the presence of a persistent chronic inflammatory infiltrate. IMT is usually benign, but in a few cases it has a tendency for malignant transformation and metastases.

CASE PRESENTATIONS

A 30-year-old male with a history of recurrent hematuria. His initial symptoms was unfrequent painless hematuria. Abdomen multislice computerized tomography (MSCT) with contrast shows an enhancing solid mass with necrotized center measuring +/- 12.9 × 16.5 × 18.9 cm and extending from cavum pelvis to cavum abdomen. Cystectomy and bilateral ureterocutaneostomy were performed. The histology report found an IMT with mitotic cells, a necrotic region, and a positive ki67, which suggest the tumor's malignant transformation. Unfortunately, the patient's overall condition continued to deteriorate, and he passed away seven days after hospital discharge.

CLINICAL DISCUSSIONS

IMT is comprised of spindel cells and inflammatory cells. IMT might become aggressive locally, recurring, or progress to malignancy. Fifty percent of IMTs are caused by rearrangements of the anaplastic lymphoma kinase (ALK) gene on chromosome 2p23, resulting in ALK-1 overexpression. A change from uniform spindled cells to atypical polygonal cells or plump cells with oval vesicular nuclei, prominent nucleoli, and mitoses is indicative of malignant transformation.

CONCLUSION

This case emphasizes the importance of continuous monitoring and raising awareness about the possibility of malignant transformation of IMT. Understanding the characteristics of the findings could result in better decision-making and outcomes.

Practical Guide to VI-RADS: MRI Protocols, Lesion Characterization, and Pitfalls

Urothelial carcinoma is the most common type of bladder cancer (BC), accounting for approximately 90% of all cases. Evaluating the depth of tumor invasion in the bladder wall (tumor staging) is essential for determining the treatment and prognosis in patients with BC. Neoadjuvant therapy followed by radical cystectomy is the most common treatment of localized muscle-invasive BC (MIBC). Therefore, it is vital to differentiate non-MIBC from MIBC. Transurethral resection of bladder tumor (TURBT) is the reference standard to determine the extent of tumor invasion into the bladder wall through tissue sampling. However, this diagnostic and therapeutic method may not adequately sample the muscularis propria, leading to a higher risk of residual disease, early recurrence, and tumor understaging in approximately 50% of patients during the initial TURBT. Multiparametric MRI can overcome some of the limitations of TURBT when evaluating BC, particularly regarding tumor staging. In this context, the Vesical Imaging Reporting and Data System (VI-RADS) classification was developed to establish standards for bladder multiparametric MRI and interpretation. It uses a 5-point scale to assess the likelihood of detrusor muscle invasion. T2-weighted MR images are particularly useful as an initial guide, especially for categories 1-3, while the presence of muscular invasion is determined with diffusion-weighted and dynamic contrast-enhanced sequences. Diffusion-weighted imaging takes precedence as the dominant method when optimal image quality is achieved. The presence of a stalk or a thickened inner layer and no evidence of interruption of the signal intensity of the muscular layer are central for predicting a low likelihood of muscle invasion. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material. See the invited commentary by Hoegger in this issue.

USP6-associated neoplasm as a tentative subset of postoperative spindle cell nodule

AIM

Postoperative spindle cell nodule (PSCN) is a pseudosarcomatous proliferative lesion of unclear molecular genetic origins.

METHODS AND RESULTS

We examined seven patients with PSCN, using routine haematoxylin-eosin (H&E) slide preparations and a series of immunostains. The latter targeted keratin, vimentin, α-smooth muscle actin (SMA), anaplastic lymphoma kinase (ALK [D5F3]), and other proteins. Ubiquitin-specific peptidase 6 (USP6) and anaplastic lymphoma kinase (ALK) gene rearrangements were also analysed by fluorescence in situ hybridization (FISH). There were histories of prior surgical intervention (n = 6) or trauma (n = 1) in all seven patients. All lesions were highly cellular and mitotically active spindle cell proliferations, with no cytologic atypia, nuclear pleomorphism, or aberrant mitoses. Immunohistochemical (IHC) staining disclosed focal, weak keratin positivity in two lesions, whereas vimentin (diffuse, strongly positive) and SMA (tram-track pattern) were present in each instance, and ALK (D5F3) was entirely negative. FISH analysis confirmed USP6 gene rearrangements in all seven cases, showing no ALK gene rearrangements. RNA sequencing results showed an MYH9::USP6 gene fusion in only one lesion (No. 6).

CONCLUSION

A subset of PSCN is marked by USP6 gene rearrangements, a genetic feature of nodular fasciitis (NF). Given its similarity to NF, a designation as USP6-associated neoplasm (UAN) seems reasonable, signifying a transient clonal neoplastic lesion.

Urinary Bladder Masses, Rare Subtypes, and Masslike Lesions: Radiologic-Pathologic Correlation

Urinary bladder masses are commonly encountered in clinical practice, with 95% arising from the epithelial layer and rarer tumors arising from the lamina propria, muscularis propria, serosa, and adventitia. The extent of neoplastic invasion into these bladder layers is assessed with multimodality imaging, and the MRI-based Vesical Imaging Reporting and Data System is increasingly used to aid tumor staging. Given the multiple layers and cell lineages, a diverse array of pathologic entities can arise from the urinary bladder, and distinguishing among benign, malignant, and nonneoplastic entities is not reliably feasible in most cases. Pathologic assessment remains the standard of care for classification of bladder masses. Although urothelial carcinoma accounts for most urinary bladder malignancies in the United States, several histopathologic entities exist, including squamous cell carcinoma, adenocarcinoma, melanoma, and neuroendocrine tumors. Furthermore, there are variant histopathologic subtypes of urothelial carcinoma (eg, the plasmacytoid variant), which are often aggressive. Atypical benign bladder masses are diverse and can have inflammatory or iatrogenic causes and mimic malignancy. ^© RSNA, 2022 Online supplemental material is available for this article.

Bladder inflammatory myofibroblastic tumor: report of four cases

Background

Inflammatory myofibroblastic tumor (IMT) of the bladder (BIMT) is a rare entity with non-specific symptoms and particular histological features. Though bladder location is very uncommon, it arises from the bladder submucosal stroma as a polypoidal growth and is easily mistaken clinically, radiologically and histologically with a malignant neoplasm. The main treatment is surgical resection. To our knowledge, few reports of this pathology have been duly informed in Latin America to date.

Case presentation

We present four case male patients evidencing bladder tumor initially treated with transurethral bladder resection, diagnosing BIMT. They had shown tumor recurrence and laparoscopic treatment were decided without evidence of new recurrence.

Conclusion

Due to the few reports of this pathology, specially in South America, it is important to know its therapeutic management and follow-up.

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.

Case Report: Recurrence of Testicular Myofibroblastic Tumor After Surgery

Inflammatory myofibroblastic tumour (IMT), also known as plasma cell granuloma (PCG) or inflammatory pseudotumour (IPT), is a distinctive, rarely metastasizing neoplasm composed of myofibroblastic and fibroblastic spindle cells accompanied by inflammatory infiltration of plasma cells, lymphocytes and/or eosinophils. IMT predominantly affects children and young adults, and the age at presentation ranges from 3 to 89 years. We present a very rare case of recurrent testicular IMT without ALK rearrangement. This case highlights the clinical characteristics and diagnostic factors associated with primary and recurrent foci of this rare tumour, along with key therapeutic approaches.

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.

Superficial angiomyxoma in a pregnant cow

A 3-year-old, pregnant, Alpine Brown cow showed a rapidly growing, pedunculated, skin mass located at the umbilical region, reaching 8 kg in weight over a 3-month period after its initial detection. Six days after parturition, the mass was completely surgically excised. During the follow-up period, the cow remained in good health, without signs of recurrence, and showed increased milk production. Histological examination of the mass revealed a loose proliferation of spindle-shaped or stellate cells, immersed in an abundant myxoid matrix with admixed numerous thin-walled blood vessels. Immunohistochemically, the tumour cells were positive for vimentin, α-smooth muscle actin, and desmin. Gross and histopathological features were compatible with superficial angiomyxoma, a subtype of angiomyxoma rarely described in humans, but not in the veterinary literature. The tumour did not infiltrate into the surrounding tissues, and there was no post-excision recurrence after 3 months. The possibility of hormonal dependence of the tumour during pregnancy is discussed based on such findings in some human cases.

Malignant transformation of inflammatory myofibroblastic tumor of urinary bladder: A rare case scenario

Inflammatory myofibroblastic tumor (IMT) previously known as inflammatory pseudotumor, plasma cell granuloma, pseudosarcoma, myxoid hamartoma or inflammatory myofibrohistiocytic proliferation is recently recognized by World Health Organization (WHO) as “IMT” and is considered as a rare benign tumor of soft tissues occurring commonly in lung, liver and mesentry and omentum. IMT is mainly identified as a lesion of children and young population. In this report, we describe a rare case of IMT occurring in a 93-year-old female in urinary bladder with initial benign presentation but demonstrating rapid malignant transformation as confirmed with morphology and immunohistochemical (IHC) stains. Our report highlights the importance of close follow for IMT showing malignant transformation along with utility of IHC stains to evaluate the degree of malignant transformation in such cases.

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.

Inflammatory myofibroblastic tumor of urinary bladder with severe hematuria: A Case report and literature review

RATIONALE

Inflammatory myofibroblastic tumor (IMT) is a rare intermediate soft tissue tumor. Rarely occurring in the urinary bladder, MTs is composed of myofibroblast differentiated spindle cells and accompanied by numerous inflammatory cells, plasma cells and/or Lymphocytes.

PATIENT CONCERNS

A 28-year-old female, with history of 2 cesarean sections 8 years ago and 2 years ago, was admitted to the emergency department for a 7-day ongoing gross hematuria with clots.

DIAGNOSES

A cystoscopy showed a tumor near the bladder neck, computed tomography (CT) showed a mass and massive blood clots in the bladder. Finally, postoperative pathological examination confirmed a diagnosis of inflammatory myofibroblastic tumor of bladder.

INTERVENTIONS

The patient was given rehydration and blood transfusion to improve the general condition. Then, emergency transurethral resection of the bladder tumor was performed.

OUTCOMES

No metastases to lymph nodes and other organs were found, and no tumor progression was revealed during 3-months of follow-up.

LESSONS

IMTs rarely occur in the urinary bladder. Due to the lack of specificity in clinical symptoms, it's difficult to arrive at a definite diagnosis before operation. Therefore, usually, the final diagnosis depends on histomorphological features and the immunohistochemical profile. Further case studies are required to study the biological behavior of this condition.

Diagnosing and Treating Inflammatory Myofibroblastic Tumor of the Bladder

Inflammatory myofibroblastic tumor (IMT) is an uncommon condition that is rarely encountered in the urinary tract. In this report, we present a case of IMT of the bladder in a woman with multiple previous pelvic surgeries. We further review the relevant literature to highlight this rare but important clinical presentation.

CT Manifestations of Inflammatory Myofibroblastic Tumors (Inflammatory Pseudotumors) of the Urinary System

OBJECTIVE

The purpose of this study is to characterize the CT manifestations of inflammatory myofibroblastic tumors (IMTs) of the urinary system in eight patients.

MATERIALS AND METHODS

The CT images of eight pathologically confirmed IMTs were retrospectively reviewed. Two of the eight IMTs occurred in the kidney, and six occurred in the bladder. Seven patients underwent both unenhanced CT and contrast-enhanced CT, and one of the patients who had a bladder tumor underwent unenhanced CT only. The site, shape, size, boundary, internal structure, and enhancement pattern of the lesions were assessed.

RESULTS

The eight patients (five men and three women) whose CT images were reviewed were 18-77 years old (mean age, 53 years). Only one lesion was seen in each of the eight patients. The IMTs occurred at the renal parenchyma (n = 1), the renal pelvis (n = 1), or the bladder (n = 6). Their shape was either roundlike (n = 7) or round (n = 1), and their size ranged from 1.5 × 2.0 cm(2) to 3.7 × 5.2 cm(2). Tumor margins were smooth (n = 5) or lobulated (n = 3), and boundaries were clear (n = 5) or ill defined (n = 3). Unenhanced CT scans showed a low density (n = 4), isodensity (n = 3), or a slightly high density (n = 1). The density noted on the unenhanced CT scans was homogeneous (n = 7) or heterogeneous (n = 1). The contrast-enhanced scans showed ring enhancement (n = 3) or significantly heterogeneous enhancement (n = 4), and the type of enhancement was persistent (n = 6) or washout (n = 1).

CONCLUSION

IMTs in the urinary system commonly occur in the superior wall or the front wall of the bladder. The observation that polypoid nodules on the bladder walls show ring enhancement on contrast-enhanced CT may be valuable in the diagnostic imaging of IMTs of the urinary system.

Dysuria and fever in a young woman diagnosed as having inflammatory myofibroblastic tumour of the urinary bladder

A 38-year-old woman presented with dysuria and fever. Her medical and family histories were unremarkable. CT scan of the abdomen revealed a polypoid mass of 4×2.6×2.2 cm. Her cystoscopy showed a 4×2 cm solid broad-based growth at trigone of the urinary bladder. She underwent transurethral resection of the urinary bladder tumour (TURBT). Histopathology revealed a poorly circumscribed proliferation of spindle cells arranged in a haphazard and fascicular manner along with many traversing blood vessels in a myxoid and hyalinised stroma. Immunohistochemistry was positive for anaplastic lymphoma kinase-1, smooth muscle actin, CD10, cytokeratin and desmin; and negative for CD34 and S-100 protein. Ki-67 proliferative index in the tumour was <1%. The patient was diagnosed as having inflammatory myofibroblastic tumour of the urinary bladder. After TURBT, her fever and urinary symptoms resolved. Her 1-month postoperative period was uneventful. She has been advised regular follow-up.

Inflammatory Myofibroblastic Tumor of Genitourinary Tract Beyond Collecting System: A Rare Case Report With Literature Review

Inflammatory myofibroblastic tumor (IMT) rarely arises in genitourinary tract especially beyond collecting system, which determines the unspecific clinic symptoms and sometimes can mimic malignancy. Therefore, IMT's diagnosis may usually be a pitfall. This case report characterizes a 35-year-old woman with a history of lower quadrant lasting pain followed by fever. Furthermore, radiologic examinations revealed that there were 2 lesions located in left adrenal area and left renalis. Owing to the anatomic complexity, the surgical resection was not complete. The pathologic diagnosis of the lesions was IMT. Adjuvant nonsteroids anti-inflammatory drugs were administrated after the operation. The symptoms were controlled finally and no further growing lesion was observed during a 1-year follow-up.Inflammatory myofibroblastic tumor is rare in genitourinary tract beyond the collecting system. Diagnosis should be based on histopathology. Presently, the authors report this rare case with the aim to share the experience regarding differential diagnosis and therapy.

Extensive rhabdomyosarcomatous differentiation in recurrent low-grade urothelial carcinoma of the bladder after transurethral resection: a case report

Introduction

Sarcomatoid carcinoma of the urinary bladder is a rare bidirectional malignant neoplasm with epithelial and mesenchymal differentiation. The epithelial component is mainly high-grade urothelial carcinoma, and the mesenchymal component includes rhabdomyosarcoma. However, proper differential diagnosis of adult rhabdomyosarcomatous tumors of the bladder can be a challenge. Moreover, low-grade urothelial carcinoma as the epithelial component of sarcomatoid carcinoma has not been reported.

Case presentation

A 64-year-old Asian man with a history of transurethral resection of low-grade urothelial carcinoma of the bladder visited our department with complaints of frequent urination and macroscopic hematuria. Computed tomography and magnetic resonance imaging demonstrated a large mass located in the anterior wall of the bladder. Pathological diagnosis of transurethral biopsy was low-grade, non-invasive papillary urothelial carcinoma, and tumor tissue was removed by total cystectomy. Immunohistochemical studies and fluorescence in situ hybridization assay of the resected neoplastic tissue revealed extensive rhabdomyosarcomatous differentiation causing the formation of a large pedunculated polyp with a papillary appearance of recurrent low-grade urothelial carcinoma. No evidence of recurrence was detected during 2 years of follow-up without further treatment.

Conclusions

Urothelial carcinoma of the urinary bladder with extensive rhabdomyosarcomatous differentiation is rare, but it should be considered in the differential diagnosis even when urothelial carcinoma coexisting with a rhabdomyosarcomatous component is low-grade and non-invasive.

Assessment of the potential diagnostic role of anaplastic lymphoma kinase for inflammatory myofibroblastic tumours: a meta-analysis

Objective

To assess the value of anaplastic lymphoma kinase for the diagnosis of inflammatory myofibroblastic tumours using a comprehensive meta-analysis.

Methods

We searched the related literature using electronic databases and manual searches. Approximately 454 cases from several countries were included in this analysis. The quality of studies included was assessed by QUADAS (quality assessment of studies of diagnostic accuracy). The diagnostic odds ratio (DOR), positive likelihood ratio (PLR), negative likelihood ratio (NLR), sensitivity and specificity were calculated to assess the role of anaplastic lymphoma kinase in the diagnosis of inflammatory myofibroblastic tumours. The overall test performance was summarised by an SROC (summary receiver operating characteristic curve). The heterogeneity and publication bias were analysed using Meta-regression and Deeks' test. All data were analysed by Stata 12.0 software.

Results

Eight studies were included according to our inclusion criteria. The overall results for the specificity, sensitivity, PLR, NLR, DOR and area under the curve (AUC) were 0.99 (95% CI 0.82-1.00), 0.67 (95% CI 0.46-0.83), 0.67 (95% CI 0.46-0.83), 60.6 (95% CI 3.3-1112.4), 0.33 (95% CI 0.19-0.60), 181 (95% CI 9-3684) and 0.95 (95% CI 0.93-0.97), respectively, while the specificity, sensitivity, PLR, NLR, DOR and AUC for bladder IMTs were 0.99 (95% CI 0.67-1.00), 0.86 (95% CI 0.58-0.96), 95.6 (95% CI 2.0-4616.2), 0.14 (95% CI 0.04-0.50), 671 (95% CI 16-28913) and 0.99 (95% CI 0.97-0.99), respectively.

Conclusion

The present meta-analysis indicated that anaplastic lymphoma kinase plays a significant role in the differential diagnosis of inflammatory myofibroblastic tumours, particularly for inflammatory myofibroblastic tumours of the urinary bladder.