Inflammatory myofibroblastic tumors of the urinary tract: a clinicopathologic study of 46 cases, including a malignant example inflammatory fibrosarcoma and a subset associated with high-grade urothelial carcinoma

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.

A diagnostically challenging case of inflammatory myofibroblastic tumor primary to the peritoneum

Introduction

Inflammatory myofibroblastic tumors are difficult to diagnose because of the lack of specific indicators. We describe a diagnostically challenging case of an inflammatory myofibroblastic tumor primary to the peritoneum.

Case presentation

The patient was a 25-year-old male who presented at our hospital with lower abdominal pain. Computed tomography revealed a mass lesion 80 mm in diameter just above the bladder. This was suspected to be a bleeding tumor of the urachus. Since malignancy could not be ruled out, surgery was planned. This revealed a fragile tumor arising from the peritoneum. Following its removal, the tumor was diagnosed by histopathological analysis as an inflammatory myofibroblastic tumor.

Conclusion

We describe a case of inflammatory myofibroblastic tumor primary to the peritoneum diagnosed by histopathology. Inflammatory myofibroblastic tumor should be considered in the differential diagnosis of abdominal wall and anterior bladder tumors.

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.

A rare huge bladder inflammatory myofibroblastic tumor treated by en bloc resection with diode laser: a case report and literature review

Background

Inflammatory myofibroblastic tumor (IMT) is a rare neoplasm with malignant potential. Bladder IMT is even rarer and mainly treated by surgical resection However, partial or radical cystectomy would affect the quality of life of patients due to major surgical trauma, and classical TURBT is hard to avoid intraoperative complications including obturator nerve reflex and bleeding etc. Therefore, the safe and effective better choice of surgical approaches become critical to bladder IMT.

Case presentation

A 42-year-old male patient was admitted to the department of urology with persistent painless gross hematuria for more than 10 days without the presentation of hypertension. Preoperative routine urine examination of red blood cells was 7738.9/HPF (normal range ≤ 3/HPF). CTU indicated a space occupying lesion (6.0 cm×5.0 cm) in the left posterior wall of the bladder with heterogeneous enhancement in the excretory phase. MRI also indicated bladder tumor with slightly equal SI on T1WI and mixed high SI on T2WI (6.0 cm×5.1cm×3.5cm) in the left posterior wall of the bladder. En bloc resection of bladder IMT with 1470 nm diode laser in combination of removing the enucleated tumor by the morcellator system was performed. Postoperative pathological examination revealed bladder IMT, with IHC positive for Ki-67 (15-20%), CK AE1/AE3, SMA, and Desmin of bladder IMT and negative for ALK of bladder IMT as well as FISH negative for ALK gene rearrangement. Second TUR with 1470 nm diode laser was performed within 6 weeks to reduce postoperative risk of recurrence due to highly malignant potential for the high expression of Ki-67 (15-20%) and negative ALK in IHC staining. The second postoperative pathology report showed chronic inflammation concomitant with edema of the bladder mucosa without bladder IMT, furthermore no tumor was observed in muscularis propria layer of bladder. No recurrence occurred during the period of 24-month follow-up.

Conclusion

En bloc resection of bladder IMT in combination of the following second transurethral resection with 1470 nm diode laser is a safe and effective surgical approach for the huge bladder IMT with highly malignant potential.

Pseudosarcomatous Fibromyxoid Tumor of the Prostate: A Rare Benign Lesion Mimicking Malignancy

Psuedosarcomatous fibromyxoid tumor (PSFT) is an uncommon, non-malignant yet locally aggressive pseudotumor found in the genitourinary system. Despite being a benign spindle cell tumor without any documented cases of metastasis, its local aggressiveness can pose a life-threatening risk. The lack of specific clinical symptoms and the infiltrative characteristics of the lesion may lead to misdiagnosis as sarcomatoid carcinoma or sarcoma. Therefore, it is crucial to distinguish PSFT histologically and through immunohistochemistry from other spindle cell tumors to avoid unnecessary investigations and treatments. This case emphasizes the difficulties in diagnosing this uncommon benign tumor because of its infrequent occurrence, limited literature, vague symptoms, and similarities in imaging results with inflammatory or infectious conditions, as well as sarcomatous neoplasms. Precise diagnosis plays a vital role in preventing unnecessary or insufficient treatment.

Inflammatory myofibroblastic tumor of the bladder in an adolescent: Case report

Inflammatory myofibroblastic tumors of the bladder (IMTB) are rare neoplasms that can occur in children. These tumors have uncertain malignant potential and can present similarly to bladder sarcomas. It is important to differentiate between IMTB and bladder sarcomas using a careful immunohistochemical approach. We report a case of IMTB in a 12-year-old girl who presented with presyncope and gross hematuria. IMTB was diagnosed through immunohistochemical analysis, and clinical improvement was observed after resection of the tumor.

The Application and Pitfalls of Immunohistochemical Markers in Challenging Diagnosis of Genitourinary Pathology

CONTEXT.—

The morphologic features of different entities in genitourinary pathology overlap, presenting a diagnostic challenge, especially when diagnostic materials are limited. Immunohistochemical markers are valuable when morphologic features alone are insufficient for definitive diagnosis. The World Health Organization classification of urinary and male genital tumors has been updated for 2022. An updated review of immunohistochemical markers for newly classified genitourinary neoplasms and their differential diagnosis is needed.

OBJECTIVE.—

To review immunohistochemical markers used in the diagnosis of genitourinary lesions in the kidney, bladder, prostate, and testis. We particularly emphasized difficult differential diagnosis and pitfalls in immunohistochemistry application and interpretation. New markers and new entities in the 2022 World Health Organization classifications of genitourinary tumors are reviewed. Recommended staining panels for commonly encountered difficult differential diagnoses and potential pitfalls are discussed.

DATA SOURCES.—

Review of current literature and our own experience.

CONCLUSIONS.—

Immunohistochemistry is a valuable tool in the diagnosis of problematic lesions of the genitourinary tract. However, the immunostains must be carefully interpreted in the context of morphologic findings with a thorough knowledge of pitfalls and limitations.

Update of Diagnosis and Targeted Therapy for ALK+ Inflammation Myofibroblastic Tumor

OPINION STATEMENT: Inflammatory myofibroblastic tumor (IMT), characterized by intermediate malignancy and a propensity for recurrence, has presented a formidable clinical challenge in diagnosis and treatment. Its pathological characteristics may resemble other neoplasms or reactive lesions, and the treatment was limited, taking chemotherapies as the only option for those inoperable. However, discovering anaplastic lymphoma kinase (ALK) protein expression in approximately 50% of IMT cases has shed light on a new diagnostic approach and application of targeted therapies. With the previous success of combating ALK+ non-small-cell lung cancers with ALK tyrosine kinase inhibitors (TKIs), crizotinib, a first-generation ALK-TKI, was officially approved by the U.S. Food and Drug Administration in 2020, to treat unresectable ALK+ IMT. After the approval of crizotinib, other ALK-TKIs, such as ceritinib, alectinib, brigatinib, and lorlatinib, have proven their efficacy on ALK+ IMT with sporadic case reports. The sequential treatments of targeted therapies in may provide the insight into the choice of ALK-TKIs in different lines of treatment for unresectable ALK+ IMT.

Locally advanced solitary fibrous tumour of the prostate

Solitary fibrous tumours (SFTs) are rare mesenchymal neoplasms composed of spindle cells, most often occurring in the pleura. SFTs arising from the prostate are exceptionally rare, with only around 40 cases reported in literature to date. We report a man in his 60s who was referred to our clinic for elevated prostate-specific antigen and presented with mild obstructive lower urinary tract and defecatory symptoms. Prostate needle-core biopsy revealed neoplastic spindle cells that strongly expressed CD34. Cross-sectional imaging demonstrated a 12 cm locally advanced heterogeneous prostate mass with intravesical extension and mass effect on the anterior rectum. Radical cystoprostatectomy with orthotopic neobladder reconstruction was performed, and the diagnosis of primary prostatic SFT was made based on histological characteristics and immunophenotyping. We present diagnostic, clinical management and prognostic considerations in patients with primary prostatic SFT.

Inflammatory myofibroblastic tumor of the urinary bladder with FN1‑ALK gene fusion: A case report

Inflammatory myofibroblastic tumors (IMTs), which are rare tumors, exhibit myofibroblastic differentiation, often with anaplastic lymphoma kinase (ALK) gene rearrangements. A subset of IMTs identified in the urinary tract have been shown to harbor a fibronectin 1 (FN1)-ALK gene fusion. In this case report, a case of an IMT with FN1-ALK fusion in the urinary bladder was presented, and its clinicopathological characteristics were reviewed. A 45-year-old female was referred to Chungbuk National University Hospital with gross hematuria. Cystoscopy revealed a solid mass in the bladder. The patient subsequently underwent transurethral resection of the lesion. The mass comprised stellate and spindled myofibroblastic cells that were arranged in loose fascicles, with a myxoid background and a mixed inflammatory infiltrate. Immunohistochemical analysis revealed that the tumor cells were positive for vimentin, cytokeratin AE1/AE3 and ALK, and focal-positive for desmin. Targeted next-generation sequencing was subsequently employed to identify the FN1-ALK fusion. To date, the patient has undergone outpatient follow-up for 18 months, with no signs of tumor recurrence. To conclude, in total, FN1 has been identified as an ALK fusion partner almost exclusively in cases of genitourinary IMTs [13 bladder IMTs (including the present case) and two uterine IMTs]. In the present case, the FN1-ALK fusion was found to involve ALK exon 19 and FN1 exon 23. By contrast, the majority of the other IMTs with an ALK fusion have involved ALK exon 20, whereas ALK fusion involving ALK exon 18 or 19 has been reported only in genitourinary IMTs. Therefore, the FN1-ALK fusion involving ALK exon 18 or 19 may be specific to a subset of IMTs arising in the urinary bladder.

A case of IgG4-related interstitial nephritis with ureteral obstruction: case report and literature review

BACKGROUND

IgG4-related disease (IgG4-RD) is a newly discovered systemic disease that can affect any organ or tissue in the body. IgG4-related kidney disease (IgG4-RKD) is relatively rare but essential to IgG4-RD. However, there are few reports of IgG4-RD mimicking malignant ureteral tumors leading to hydronephrosis. We report here a rare case of IgG4-RD involving the ureter.

CASE PRESENTATION

An 87-year-old man presented to our nephrology department with anorexia, nausea, and acute kidney injury in November 2020. Urinary computed tomography (CT) examination revealed a right lower ureter mass with right renal and ureter hydronephrosis. The serum level of IgG4 was 1890 mg/dL, and the concurrently renal biopsy revealed extensive infiltration of IgG4-positive plasma cells in renal interstitium, which was diagnosed as IgG4-associated tubule-interstitial nephritis(IgG4-TIN). The renal function improved significantly after double-J tube implantation of the right ureter and moderate-dose hormone therapy. The serum IgG4 decreased to the normal range, and the right lower ureter mass almost disappeared after one year of low-dose hormone maintenance therapy.

CONCLUSION

IgG4-RD can present as a mass in the renal pelvis and (or) ureter, leading to hydronephrosis. Therefore, early recognition of this disease is significant. Most patients respond well to hormonal therapy to avoid surgical treatment due to misdiagnosis as malignant tumors, causing secondary harm to patients.

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.

Primary inflammatory myofibroblastic tumour of the liver: a clinicopathological and genetic study including a subset with ETV6::NTRK3 fusion

AIMS

Inflammatory myofibroblastic tumour (IMT) is an intermediate neoplasm and rarely occurs in the liver. The aim of this study was to analyse the clinicopathological and genetic features of the largest primary hepatic IMT.

METHODS AND RESULTS

A total of 10 cases were identified (four males and six females aged 1-48 years, median = 35 years) from 2011 to 2021, which accounted for 2.5% of IMTs occurring in all organ systems. Histological findings revealed that myofibroblastic/fibroblastic cells with inflammatory infiltration and focal hypocellularity were observed in three children. Immunostaining showed ALK-diffuse cytoplasmic positive in six cases (six of 10; 60%) and pan-TRK nuclear positive in three cases (three of 10; 30%). Hypercellular pattern was detected in ALK-positive IMTs and obvious collagenous/myxoid matrix was observed in the pan-TRK-positive subgroup. ALK rearrangement was demonstrated in three of five interpretable ALK-positive IMTs by fluorescence in-situ hybridisation (FISH), and one case failed due to poor sample quality. Next-generation sequencing indicated an IMT with TFG::ALK and FCHSD2::ALK fusion and TP53 mutation. ETV6::NTRK3 fusion was confirmed by RT-PCR, but FISH-negative results were found in two of three cases with pan-TRK-positive IMTs. No genetic alteration was detected in one tumour. One patient died 1 year after biopsy, while nine patients survived without evidence of disease in the follow-up surveillance (17-119 months).

CONCLUSIONS

This article describes the first example of primary paediatric hepatic IMTs with ETV6::NTRK3 fusion. Besides the common ALK-positive subgroup, the proportion of NTRK3 fusion is high. Recognising the association between clinicopathological and molecular alterations is critical to accurate diagnosis of hepatic IMTs.

Case report: Emergency management of spontaneous rupture of the inflammatory myofibroblastic tumor of the urinary bladder

Acute abdomen caused by spontaneous rupture of the inflammatory myofibroblastic tumor of the urinary bladder (IMTUB) is a rare clinical emergency of the urinary system.It is difficult to distinguish it from spontaneous rupture of bladder caused by other causes before surgery. An emergency case of spontaneous rupture of IMTUB was reported. A 57-year-old middle-aged woman was admitted to the hospital because of “acute lower abdominal pain for 5 hours”. No history of smoking and gross hematuria. The physical examination revealed visible abdominal tenderness as well as signs of shock. A pelvic CT scan shows a space-occupying lesion above the bladder with massive accumulation of blood. When the nature of the tumor could not be determined, emergency laparotomy and partial cystectomy were performed, and postoperative pathology confirmed cystitis myofibroblastic tumor. No local recurrence or distant metastasis of the tumor was observed during the regular follow-up period of 6 months. IMTUB should focus on prevention and treatment, with a combination of preoperative examination and postoperative pathology, and finally implement highly individualized treatment.

Inflammatory Myofibroblastic Tumor in Bladder with Multiple Vesicocutaneous Fistula in Pediatric Patient: A Rare Case Report

Inflammatory myofibroblastic tumor (IMT) is a rare tumor that occurs at any age from childhood to late adulthood and may have a slight male predilection. A 7-year-old female presented with gross hematuria and a lump in the lower abdomen since 1 month prior to admission. The complaints were also accompanied by weight loss, abdominal pain and anemia. Ultrasound examination, Cystography, CT-Scan and MRI showed that mass in the bladder. Histopathology examination confirmed diagnosis for IMT, thus, radiology plays an important role in supporting histologic examination for diagnosis and evaluation of IMT.

Spindle cell tumours of the ureter: Operation or observation?

We describe a rare case of inflammatory spindle cell tumour of the ureter in a patient who presented with renal colic and macroscopic haematuria. Pyeloscopy revealed a partially obstructing mass at the proximal right ureter which confirmed a myofibroblastic tumour on biopsy. Radical nephrectomy was performed which confirmed a spindle cell tumour of the ureter confined to the resection margins. Follow-up imaging in 12 months did not illustrate recurrence or metastasis. The decision to perform a nephrectomy was due to the limited experience with this tumour. Reports illustrate that this tumour is unlikely to metastasize, and thus be managed conservatively.

•

Benign spindle cell tumours/inflammatory myofibroblastic tumours (IMTs) of the ureter are exceedingly rare.

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Histologically they may mimic low grade genitourinary sarcomas and therefore good histological assessment needs to be sort.

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Kidney sparing surgery should be offered to suitable patients.

•

Close clinical and radiological observation can be offered to suitable patients.

•

Surgery is likely to be curative without the need for ongoing surveillance.

Inflammatory myofibroblastic tumour of the bladder: a case report and review of the literature

Inflammatory myofibroblastic tumours (IMTs) are rare neoplasms of uncertain malignant potential that closely resemble other more aggressive spindle cell tumours. The distinction of IMT from the latter is of importance. We report a case of IMT in a 27-year-old man who presented with intermittent painless, macroscopic haematuria and was found to have a large bladder mass arising from the dome of the bladder. The tumour was resected transurethrally, and histology and immunohistochemistry were consistent with an IMT of the bladder. Our patient remained asymptomatic at follow-up 3 months later, when cystoscopy noted no regrowth of the residual tumour. Transurethral resection resection of bladder tumour, partial cystectomy and radical cystectomy form the mainstay of treatment of IMT. However, the optimal management of this condition remains uncertain due to the sparsity of reported cases.

Anaplastic lymphoma kinase inhibitor therapy in the treatment of inflammatory myofibroblastic tumors in pediatric patients: Case reports and literature review

BACKGROUND

Inflammatory myofibroblastic tumors (IMTs) are a rare subtype of inflammatory pseudotumor frequently associated with rearrangement of the anaplastic lymphoma kinase (ALK) gene. Their treatment has historically relied on at-times challenging and morbid surgical excision. Recent studies have shown that neo/adjuvant therapy with ALK inhibitors can significantly enhance outcomes in select patients.

METHODS

A systematic literature review was performed to characterize comprehensive treatment of ALK-positive IMTs in the pediatric population. This report also includes two patients from our home institutions not previously reported in the literature.

RESULTS

We identified a total of 27 patients in 12 studies in addition to 2 patients from the senior authors' institution for a total of 29 patients (median age, 7 years; 52% male). The IMTs comprised a wide range of anatomic locations. Almost half (12, 41.3%) were treated with ALK-inhibitors alone and felt to be in remission. The remainder was treated with ALK-inhibitors either before or after surgery and had a curative response.

CONCLUSIONS

ALK-positive IMTs can be successfully treated with ALK-inhibition alone or in combination with surgical resection. Further genetic characterization may be helpful in determining more precise treatment and defining needed durations thereof.

Clinicopathological analysis and outcomes of inflammatory myofibroblastic tumours of the urinary bladder

OBJECTIVES

To describe clinical, imaging, and histopathological characteristics of inflammatory myofibroblastic tumour (IMT) of the urinary bladder and provide initial management and surveillance recommendations.

PATIENTS AND METHODS

We identified patients with IMT of the bladder treated at our facility from 1998 to 2020. Categorical variables were analysed with chi-square and Fisher's exact tests and continuous variables with the Mann-Whitney U-test. Kaplan-Meier analysis was performed for recurrence-free survival.

RESULTS

IMT was diagnosed in 35 patients with median (interquartile range [IQR]) follow-up of 20 (11.5-68.5) months. At initial diagnosis 86% were clinically organ-confined, 9% locally advanced, and 5% metastatic. Majority of patients (92%) had residual disease on re-staging transurethral resection (TUR). Of the 15 patients with organ-confined disease managed initially with TUR alone, five (33%) recurred at a median (IQR) of 5 (3.0-5.5) months from initial diagnosis. Presentation with visible haematuria was associated with recurrence (100% in recurrence vs 40% in non-recurrence groups, P = 0.044). There were no patients who developed a recurrence beyond 6 months after diagnosis. Partial or radical cystectomy was required in 23% and 9% of patients, respectively. One patient presented with metastatic disease associated with anaplastic lymphoma kinase (ALK) translocation and achieved a durable complete remission with 7 months of crizotinib therapy.

CONCLUSIONS

No patient with IMT treated with aggressive endoscopic management developed recurrences beyond 6 months. There were additionally no recurrences noted after definitive radical or partial cystectomy. These data support organ sparing therapy with aggressive endoscopic management and short-term surveillance in patients with localised IMT, with extirpative surgery reserved for refractory cases.

Case Report: Circulating Tumor Cells as a Response Biomarker in ALK-Positive Metastatic Inflammatory Myofibroblastic Tumor

Inflammatory myofibroblastic tumors (IMTs) are locally aggressive malignancies occurring at various sites. Surgery is the mainstay of treatment and prognosis is generally good. For children with unresectable or metastatic tumors, however, outcome is particularly severe, limited also by the lack of predictive biomarkers of therapy efficacy and disease progression. Blood represents a minimally invasive source of cancer biomarkers for real-time assessment of tumor growth, particularly when it involves the analysis of circulating tumor cells (CTC). As CTCs potentially represent disseminated disease, their detection in the blood correlates with the presence of metastatic lesions and may reflect tumor response to treatment. Herein, we present a case report of a 19-year-old boy with an ALK-positive IMT of the bladder, proximal osteolytic and multiple bilateral lung lesions, who received ALK inhibitor entrectinib postoperatively and underwent longitudinal CTC analysis during treatment. Antitumor activity of entrectinib was demonstrated and was accompanied by regression of lung lesions, elimination of CTCs from the blood and no development of relapses afterwards. Therapy continued without any clinical sign of progression and 24 months since the initiation of treatment the patient remains symptom-free and disease-free.

A rare noncancerous but life-threatening tumor in urinary bladder

IMT is a rare but sometimes life-threatening tumor. Although presenting with muscle invasion, local surgical resection with TURBT and close follow-up are adequate with bladder function and life quality preservation compared to partial cystectomy.

Pseudosarcomatous myofibroblastic proliferations of the urinary bladder are neoplasms characterized by recurrent FN1-ALK fusions

Pseudosarcomatous myofibroblastic proliferation is a descriptive term that designates a group of clinically indolent genitourinary lesions that most commonly arise in the urinary bladder. Given that pseudosarcomatous myofibroblastic proliferation may show morphologic overlap with inflammatory myofibroblastic tumor, the relationship, if any, between the two entities has been unclear. Moreover, pseudosarcomatous myofibroblastic proliferations are known to be positive for ALK immunohistochemistry in a subset of cases, although an inconsistent association with ALK rearrangement (ranging from 0 to 60%) has been reported. The objectives of this study were to determine the frequency of ALK rearrangement and to identify fusion partners using fluorescence in situ hybridization (FISH) and targeted RNA sequencing studies in a contemporary series of 30 pseudosarcomatous myofibroblastic proliferations of the urinary bladder, as well as to investigate ROS1 status by immunohistochemistry. ALK immunohistochemistry was positive in 70% (21/30) of pseudosarcomatous myofibroblastic proliferations; ROS1 immunohistochemistry was consistently negative (0/28). ALK rearrangements were detected by FISH in 86% (18/21) of cases, correlating with ALK immunohistochemical positivity in all but 3 cases. Of eight cases confirmed to be ALK rearranged by FISH, targeted RNA-sequencing detected FN1-ALK fusions in seven (88%) cases, which involved exons 20-26 of FN1 (5') and exon 18-19 of ALK (3'). In conclusion, ALK rearrangements are frequent in pseudosarcomatous myofibroblastic proliferations, typically involving exon 19, and FN1 appears to be a consistent fusion partner. Given the significant clinicopathologic differences between inflammatory myofibroblastic tumor and pseudosarcomatous myofibroblastic proliferation, our findings provide further support for classification of pseudosarcomatous myofibroblastic proliferation as a distinct clinicopathologic entity, and propose the alternate terminology "pseudosarcomatous myofibroblastic neoplasm of the genitourinary tract."

Inflammatory Myofibroblastic Tumor After Treatment of Wilms Tumor in a 6-Year-Old Boy: A Case Report and Literature Review

Inflammatory myofibroblastic tumor (IMT) is a rare tumor with an indolent course. It is less often reported as a second tumor that occurs after treatment of malignant tumors in pediatric patients. Here, we report a case of IMT following Wilms tumor (WT), and conduct a literature review concerning IMTs and WT to evaluate the diagnostic possibility of IMT as a second tumor. The coexistence of the 2 tumors may cause confusion as to whether they share genetic links or that IMTs may appear as late effects of the treatment of WT.

Prostatic stromal proliferations: a review

Prostatic stromal proliferations account for the majority of benign tumour-like lesions in the prostate. The most common is nodular hyperplasia, seen in a majority of elderly men. Diagnostic difficulty is encountered with some variants, including stromal hyperplasia with atypia, characterised by degenerative changes of myofibroblasts. In contrast with benign stromal tumours, malignant stromal tumours of the prostate are rare, accounting for less than 0.1% of all prostatic malignancies. The most common are rhabdomyosarcoma (paediatric) and leiomyosarcoma (adults); others include phyllodes tumour and stromal sarcoma. Some authors lump malignant tumours with poor outcome (e.g., phyllodes tumour and stromal sarcoma) with benign stromal tumours (e.g., stromal hyperplasia with atypia, leiomyoma), considering them collectively to be of uncertain malignant potential, but this approach is discouraged. This review presents a contemporary approach to classification and diagnosis of prostatic stromal tumours.

Inflammatory myofibroblastic tumor of the urinary bladder: A prognostically favorable spindle cell neoplasm

Inflammatory myofibroblastic tumor (IMT) is a rare, benign spindle cell neoplasm of the urinary bladder with a presentation concerning a malignant disease. Oftentimes, these tumors pose a diagnostic dilemma because of a significant overlap with malignant spindle cell tumors in terms of clinical presentation, gross findings, and immunohistopathologic profile. A 28-year-old female presented to us with gross hematuria. Upon work up, the presence of a bladder mass was noted. Cystoscopy and transurethral resection of bladder tumor were done and histopathologic results revealed an IMT. Partial cystectomy was then performed for complete surgical resection.

A Case of Simultaneously Diagnosed Lung Adenocarcinoma and Endobronchial Inflammatory Myofibroblastic Tumor with Two Distinct Types of ALK Translocation

A 61-year-old male patient was simultaneously diagnosed with lung adenocarcinoma and inflammatory myofibroblastic tumor (IMT). The lung adenocarcinoma and IMT harbored two distinct types of ALK translocation, LOC101927285-ALK, and TPM3-ALK, respectively. The ALK Ventana showed strong positivity on both lesions. The patient was therefore given an endobronchial cryotherapy and ALK inhibitor crizotinib. The tumors showed durable response however the left lung adenocarcinoma relapsed at 17th month post-crizotinib treatment. Tissue re-biopsy on the resistant tumor revealed an ALK exon 23 C1156Y missense mutation in addition to LOC101927285-ALK mutation. Further RNA-based sequence uncovered that the noncoding region rearrangement is the fusion mutation of EML4-ALK. The patient was therefore received alectinib, and the tumor exhibited partly response. Overall, it is very rare that two types of pulmonary tumors exist in one patient driven by two distinct ALK fusions, which emphasizes the necessity of gene sequencing in clinical decision-making and individualized therapy.

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.

A Rare Case of Inflammatory Myofibroblastic Tumor of the Prostate and Review of the Literature

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is a rare type of soft-tissue neoplasm. IMT of the urinary tract is more common in the bladder and kidneys. Prostatic IMT is extremely rare.

CASE REPORT

We present a rare case of IMT of the prostate and a literature review on this condition. The patient was a 72-year-old man who presented with urinary symptoms. Transrectal needle biopsy of the prostate revealed prostatic adenocarcinoma with nodular hyperplasia. Radical prostatectomy revealed IMT without residual adenocarcinoma. On immunohistochemical examination, the tumor cells showed positive immunoreactivity for α-smooth muscle actin, CD10, CD34, and desmin but negative immunoreactivities for anaplastic lymphoma kinase (ALK), receptor tyrosine kinase (c-KIT), and S-100 protein. The patient underwent regular follow-up examination. No recurrence was observed 4 months after the diagnosis.

CONCLUSION

This was a case of IMT arising in the prostate. Pathologists should be aware of such an entity whenever they see spindle-cell lesions in the transrectal needle biopsy of the prostate.

A Rare Case of Inflammatory Myofibroblastic Tumor of the Prostate and Review of the Literature

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is a rare type of soft-tissue neoplasm. IMT of the urinary tract is more common in the bladder and kidneys. Prostatic IMT is extremely rare.

CASE REPORT

We present a rare case of IMT of the prostate and a literature review on this condition. The patient was a 72-year-old man who presented with urinary symptoms. Transrectal needle biopsy of the prostate revealed prostatic adenocarcinoma with nodular hyperplasia. Radical prostatectomy revealed IMT without residual adenocarcinoma. On immunohistochemical examination, the tumor cells showed positive immunoreactivity for α-smooth muscle actin, CD10, CD34, and desmin but negative immunoreactivities for anaplastic lymphoma kinase (ALK), receptor tyrosine kinase (c-KIT), and S-100 protein. The patient underwent regular follow-up examination. No recurrence was observed 4 months after the diagnosis.

CONCLUSION

This was a case of IMT arising in the prostate. Pathologists should be aware of such an entity whenever they see spindle-cell lesions in the transrectal needle biopsy of the prostate.

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.

Organ-associated pseudosarcomatous myofibroblastic proliferation with ossification in the lower pole of the kidney mimicking renal pelvic carcinoma: A case report

BACKGROUND

Organ-associated pseudosarcomatous myofibroblastic proliferation (PMP) is a very rare disorder. In the urogenital tract, PMP preferentially involves the urinary bladder; kidney involvement is rare. Here, we report a rare case of PMP with ossification in the lower pole of the kidney, which mimics urothelial carcinoma or an osteogenic tumor.

CASE SUMMARY

A Chinese man was admitted to our hospital due to intermittent hematuria for more than 1 mo. Enhanced renal computed tomography revealed a mass in the left renal pelvis and upper ureter. The preoperative clinical diagnosis was renal pelvic carcinoma, determined by imaging examination and biopsy. After a standard preparation for surgery, the patient underwent retroperitoneoscopic radical nephroureterectomy. The operative findings were an extensive renal tumor (6 cm × 4.5 cm × 4.5 cm) invading the lower pole of the kidney and upper ureter. The final pathological diagnosis was organ-associated PMP with ossification. After 6-mo follow-up, no recurrence or metastasis was found.

CONCLUSION

This case of PMP was unusual for its mimicking renal pelvic carcinoma in imaging examinations, making biopsy necessary.

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.

Transurethral Resection for the Treatment of an Inflammatory Myofibroblastic Tumor of the Urinary Bladder: A Case Report

Inflammatory myofibroblastic tumors (IMT) of the urinary bladder is a remarkably rare bladder tumor. To this day, no standardized treatment protocol has been recognized. Here we report a case of bladder IMT in a 14-year-old girl presenting with urgency, frequency, and gross painless hematuria for a week. Complete excision of the bladder IMT was amenable with transurethral resection of bladder tumor (TURBT). Follow-up cystoscopy did not detect any recurrence. Minimally invasive bladder-sparing treatments are a valid option for treating IMT of the bladder.

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.

Metastatic inflammatory myofibroblastic tumor of the bladder

A 61-year-old male presented with gross hematuria and transurethral resection of bladder tumor revealed inflammatory myofibroblastic tumor (IMT). Due to extent of disease leading to ureteral obstruction and hydronephrosis, radical cystectomy (RC) with ileal conduit urinary diversion was performed. Five months after RC, the patient presented with decreased urine output. Exploratory laparotomy revealed mass in right colon and right hemicolectomy revealed metastatic IMT to the bowel and pericolonic fat. To our knowledge, this is the first report of primary IMT of the bladder metastasizing to other organs.

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.

Mesenchymal Neoplasms of the Genitourinary System: A Selected Review with Recent Advances in Clinical, Diagnostic, and Molecular Findings

Mesenchymal neoplasms of the genitourinary (GU) tract often pose considerable diagnostic challenges due to their wide morphologic spectrum, relative rarity, and unexpected incidence at GU sites. Soft tissue tumors arise throughout the GU tract, whether from adventitia surrounding or connective tissues within the kidneys, urinary bladder, and male and female genital organs. This selected article focuses on a subset of these lesions, ranging from benign to malignant and encompassing a range of patterns of mesenchymal differentiation, where recent scholarship has lent greater insight into their clinical, molecular, or diagnostic features.

Ureteral inflammatory myofibroblastic tumor: A case report and literature review

RATIONALE

Inflammatory myofibroblastic tumor (IMT) is a rare soft-tissue neoplasm which has been described in a variety of locations. In the urogenital system, IMT predominantly occurs in the bladder and the kidney. IMT arising from the ureter is exceedingly rare and has been sporadically reported before.

PATIENT CONCERNS

We reported an extremely exceptional case of IMT arising from the ureteral submucosa in a 54-year-old man. The patient was hospitalized with the main complaint of intermittent and moderate left abdominal pain for 2 months.

DIAGNOSES AND INTERVENTIONS

Computed tomography scan revealed a nearly circular mass in the left upper ureter. Ureteroscopy showed that the ureteral lumen mucosa was smooth. However, the upper ureter was compressed and narrow. Renal dynamic imaging was performed and the measured glomerular filtration rate was 46.98 mL/min (right renal) and 9.77 mL/min (left renal), respectively. A retroperitoneoscopic radical nephroureterectomy was performed. The histopathologic examination revealed that the soft-tissue neoplasm was mainly composed of myofibroblastic spindle cells proliferation with mixed inflammatory infiltrate, containing lymphocytes, neutrophils, and eosinophils. On immunohistochemical staining, the tumor was positive for smooth muscle actin and Ki-67 (<1%+), indicating a confirmed diagnosis of ureteral IMT.

OUTCOMES

The patient recovered well with no occurrence of complications. At 3-year follow-up, there was no radiologic evidence of tumor recurrence or metastasis and the man was well.

LESSONS

Ureteral IMT is extremely rare and often asymptomatic, resulting in delayed diagnosis. Radiologic evidences may be suggestive of the diagnosis of IMT. However, it is necessary to make an accurate diagnosis in terms of histopathologic assessment. Complete lesion excision is the best therapeutic approach with rare recurrences and excellent survival.

A rare inflammatory myofibroblastic bladder tumor masquerading urachal carcinoma

Inflammatory pseudotumor is a rare benign condition of unknown cause. A 19-year-old female presented with gross hematuria and storage symptoms to the emergency. Contrast-enhanced computed tomography scan revealed a mass of 5 cm × 6 cm involving the dome and anterior wall of the bladder. Urachal carcinoma was kept as a possibility and transurethral biopsy of the aforementioned lesion was performed. The histopathology revealed inflammatory myofibroblastic tumor (IMT) of the bladder. A laparoscopic partial cystectomy was undertaken with adequate resection margins and the histopathology of the lesion confirmed IMT. When evaluating a mass in the genitourinary tract in a young individual, IMT should be considered as a possibility.

Update of the International Consultation on Urological Diseases on bladder cancer 2018: non-urothelial cancers of the urinary bladder

PURPOSE

To provide a comprehensive update of the joint consultation of the International Consultation on Urological Diseases (ICUD) for the diagnosis and management of non-urothelial cancer of the urinary bladder.

METHODS

A detailed analysis of the literature was conducted reporting on the epidemiology, etiology, diagnosis, treatment and outcomes of non-urothelial cancer of the urinary bladder. An international, multidisciplinary expert committee evaluated and graded the evidence according to the Oxford System of Evidence-based Medicine modified by the ICUD.

RESULTS

The major non-urothelial cancers of the urinary bladder are squamous cell carcinoma, adenocarcinoma, and neuroendocrine tumors. Several other non-urothelial tumors are rare but important to identify because of their aggressive behavior when compared to urothelial bladder tumors. Radical cystectomy and urinary diversion, preceded by neoadjuvant radiation or chemotherapy in some of these tumors, is the main method or treatment for resectable disease. Adjuvant therapy is not usually successful and no novel targeted or immunotherapeutic agents have been identified to provide benefit. Patients with small cell neuroendocrine tumors of the bladder should be offered chemotherapy before surgery. Because non-urothelial cancers are usually locally advanced and/or metastatic at the time of diagnosis, 5-year survival is generally poor.

CONCLUSIONS

Non-urothelial cancers of the urinary bladder are rare and mostly lack established protocols for treatment. The prognosis of most of these tumors is poor because they are usually advanced at the time of diagnosis. A multimodal treatment approach should be considered to improve outcomes.

Pseudosarcomatous myofibroblastic proliferations of the genitourinary tract are genetically different from nodular fasciitis and lack USP6, ROS1 and ETV6 gene rearrangements

AIMS

Pseudosarcomatous myofibroblastic proliferations of the genitourinary tract have a debatable relationship with inflammatory myofibroblastic tumour (generally lacking ALK rearrangement); however, they share several overlapping features with nodular fasciitis of soft tissue. As rearrangement of the USP6 gene has been recently recognised as a recurrent alteration in soft tissue nodular fasciitis, and several other alternative gene fusions have been recently recognised in inflammatory myofibroblastic tumour, the aim of this study was to investigate whether USP6, ROS1 or ETV6 rearrangements were present in these lesions (12 cases).

METHODS AND RESULTS

Fluorescence in-situ hybridisation analysis was performed by the use of bacterial artificial chromosome-derived break-apart probes against USP6, ROS1, and ETV6. Two cases with adequate genetic material from recent paraffin tissue blocks were also tested by use of a solid tumour gene fusion detection assay via next-generation sequencing, targeting >50 known genes involved in recurrent fusions. None of the genitourinary pseudosarcomatous myofibroblastic proliferations was found to harbour USP6 (0/12), ROS1 (0/8) or ETV6 (0/7) rearrangements, and no gene fusions were detected in two cases studied by sequencing.

CONCLUSIONS

Despite overlap in histological and immunohistochemical features between pseudosarcomatous myofibroblastic proliferation and nodular fasciitis, these tumours lack the recently recognised USP6 rearrangements that occur in nodular fasciitis, as well as alternative fusions found in ALK-negative inflammatory myofibroblastic tumours. At present, this diagnosis remains based primarily on clinical, histological and immunohistochemical features.

A Rare Case of Ureteral IgG4 Disease Masquerading as Urothelial Carcinoma

The present paper described a rare case of ureteral IgG4-related disease (IgG4-RD) that mimicked urothelial carcinoma. An otherwise healthy patient presented with computed tomography, ureteroscopic, and biopsy findings that were suspicious of urothelial carcinoma. The patient received a right nephroureterectomy. Histopathology showed ureteral IgG4-RD, without evidence of urothelial carcinoma. Accurate diagnosis of this rare entity should be based on clinical, biochemical, and histopathological findings.

PET-CT evaluation of the curative effect of crizotinib on malignant myofibroblastoma with rare mutation of ALK R401: a case report and literature review

Objective

The purpose of this article is to explore the targeted treatment of malignant myofibroblastoma and evaluate the role of neoplasm metabolite markers in the evaluation of efficacy after targeted therapy.

Method

This report described a case of myofibroblastic sarcoma with rare mutation of ALK R401 in a 58-year-old man prescribed with crizotinib, to evaluate its curative effect by positron emission tomography coupled with computed tomography (PET-CT). After the progressive disease in the brain, bevacizumab combined with crizotinib was administered. The Response Evaluation Criteria in Solid Tumors (RECIST), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were used to assess the efficacy. The efficacy was assessed by comparing changes in MTV and TLG.

Result

After the treatment of crizotinib, the tumor volume was decreased. However, bevacizumab combined with crizotinib had not improved the prognosis. The change of MTV and TLG was consistent with the efficacy. The increase of MTV and TLG is an early indicator of the poor prognosis of patients.

Conclusion

The treatment of the crizotinib patient with the mutation of ALK R401 was effective. The values of MTV and TLG reflected the prognosis earlier than RECIST.

Testicular Inflammatory Myofibroblastic Tumor: A Known Entity at a Very Rare Site

Inflammatory myofibroblastic tumors (IMT) are distinctive lesions of unknown etiology, composed of myofibroblastic spindle cells with an associated inflammatory background. They can occur in a wide age range and at all anatomic sites, but most frequently they can be observed in the lung (especially in pediatric cases), abdomen, or retroperitoneum. The urinary bladder is one of the most common sites in urological cases. We present a very rare case of IMT of the testis. Clinically, a 40-year-old patient showed a palpable painless lesion of the right testis. Ultrasound examination showed two solid intratesticular foci. During surgical intervention, the intraoperative frozen section revealed mesenchymal tumors admixed with an uncommon inflammatory infiltrate, consistent with a reorganized abscess. Despite the benign result, orchiectomy was performed due to the multifocal presentation and the large size of 3 cm. The final diagnosis was IMT without ALK-rearrangement. Incomplete resection increases the risk of local relapses to 30%. In this case, a complete resection could be achieved and the patient is free of tumor 15 months later.

Rare Lesions and Tumors of the Urinary Bladder. Selected Issues

Morphological variants of urothelial cancer have been recently described. The timely identification and recognition of these histological variants should avoid their misinterpretation as benign lesions. We emphasize the peculiar features of these variants because some may require different/specific therapeutic approaches.

Mesenchymal tumors of the prostate

Mesenchymal tumors of the prostate are rare but often cause considerable diagnostic difficulty when encountered. These may be either benign or malignant and can arise within the prostate gland or in adjacent tissues. This review covers prostatic stromal proliferations (prostatic stromal tumor of uncertain malignant potential and stromal sarcoma), solitary fibrous tumor, myofibroblastic proliferations, smooth muscle neoplasms (leiomyoma and leiomyosarcoma), gastrointestinal stromal tumor, schwannoma, rhabdomyosarcoma, sarcomatoid carcinoma, postradiation sarcoma, and mixed epithelial stromal tumor of the seminal vesicle. Differential diagnostic considerations are emphasized, including descriptions of helpful histological and/or clinical clues and the use of adjuvant diagnostic techniques.

Characteristics of bladder neoplasms in the young population of Saudi Arabia

Context:

Bladder neoplasms are a well-studied subject in medicine. However, the evidence of bladder neoplasms in children and the young adult population (≤40 years), particularly in Saudi Arabia, is lacking.

Aims:

The aims of this study were to identify histopathological characteristics as well as clinical features, prognosis, and treatment of bladder neoplasms in this age group in a single tertiary referral center, Riyadh, Saudi Arabia.

Settings and Design:

A retrospective cohort study.

Materials and Methods:

Children and young adults (≤40 years) diagnosed with epithelial and mesenchymal bladder neoplasms from 1994 to 2017.

Statistical Analysis Used:

Descriptive data are presented as mean (standard deviation) or median (interquartile range) for continuous variables and n (%) for categorical variables. Statistical Package for Social Sciences version 23 was used.

Results:

Thirty-eight cases were identified. The majority, 71.1% (n = 27) were male. The median age of diagnosis was 33 years ranging from 1 to 40 years. Nearly 45% (n = 17) were smokers. Macroscopic hematuria was present in 57.8% (n = 22). The most common histopathology was papillary urothelial carcinoma (n = 18, 58%). All mesenchymal neoplasms accounted for 18.4% (n = 7). Of all malignancies, 63.2% (n = 24) and 44.7% (n = 17) were low stage and low grade, respectively. Transurethral resection of bladder tumor (TURBT) was conducted for 81.6% (n = 31). The mean length of follow-up was 36.05 months (±39.4 months). Recurrence occurred in 15.8% (n = 6) and 7.9% (n = 3) had progression. Distant metastasis was reported in 5.3% (n = 2). Nearly 8% (n = 3) died during their follow-up.

Conclusions:

Bladder malignancies at the early fourth decade of life tend to be a low stage and low grade. The most common histopathology was papillary urothelial carcinoma. Management should be based on the clinical and histopathological features. However, most of the patient underwent TURBT.