Soft tissue tumors of the urinary bladder, Part I: myofibroblastic proliferations, benign neoplasms, and tumors of uncertain malignant potential

Common Diagnostic Challenges in Genitourinary Mesenchymal Tumors: A Practical Approach

Mesenchymal neoplasms within the genitourinary tract include a wide spectrum of tumors, ranging from benign to malignant, and tumors of uncertain malignant potential. Except for stromal tumors of the prostate, which originate from the specific prostatic stroma, these neoplasms generally resemble their counterparts in other body sites. The rarity of these neoplasms and the limitation associated with small biopsy samples present unique diagnostic challenges for pathologists. Accurate diagnosis is paramount, as it significantly influences prognosis and guides management and treatment strategies. This review addresses common diagnostic scenarios, discusses key differential diagnoses, and sheds light on potential diagnostic pitfalls.

Hemangioma of the Urinary Bladder: A Brief Narrative Review of Their Diagnosis, Histology, and Treatment Options

BACKGROUND

Hemangioma of the urinary bladder is a rare benign tumor. Although benign, their presenting symptoms are alarming for both patients and doctors, and their rarity makes them challenging to correctly diagnosis and treat. This review paper summarizes current knowledge about hemangioma of the urinary bladder, treatment options, and follow-up modalities.

SUMMARY

After the kidney, the bladder is the second most common location of hemangiomas in the urinary tract. There is painless gross hematuria on clinical presentation once the lesion has eroded the urothelium. Magnetic resonance imaging (MRI) has been reported to be valuable in diagnosing soft-tissue hemangiomas. Cystoscopic findings of a sessile, blue, multilocular mass suggest hemangioma. Most tumors are solitary, smaller than 3 cm, and have smooth or irregular surfaces. Histologically, lesions comprise numerous proliferative capillaries with thin-walled, dilated, blood-filled vessels lined with flattened endothelium. The treatment of patients with hemangioma has been controversial. It depends on the tumor size and the degree of penetration. The prognosis of these tumors is excellent.

KEY MESSAGES

Despite the widespread use of MRI, CT, and endoscopy in evaluating hematuria, hemangioma remains one of the rarest bladder tumors. Moreover, only a histological examination can confirm the diagnosis. Transurethral resection, fulguration, and YAG laser ablation are standard treatments for small tumors. In terms of follow-up, cystoscopy after 6 months of treatment helps assess recurrence. In addition, MRI is a practical, noninvasive technique for follow-up of small hemangiomas.

A Huge Hemangioma of the Urinary Bladder: A Case Report and Literature Review

Cavernous hemangioma of the bladder is a benign and very rare vascular tumor. It can be isolated or part of a syndrome. Neither clinical symptoms nor imaging modalities lead to a definitive diagnosis as there are no specific findings on imaging studies or specific symptoms. Painless gross hematuria is the most common chief complaint and presentation and should never be underestimated. Here, we report a case of a large hemangioma of the urinary bladder in a young man who presented with recurrent recent episodes of painless gross hematuria and, surprisingly, with a previous episode of painless hematuria 15 years ago, which was treated successfully with partial cystectomy. We discuss the clinical features, evaluation, diagnosis, biopsy, management, the challenges encountered in treatment, and assert the value of tissue diagnosis and follow-up pattern and period. Due to the rarity of the tumor and lack of trials and evidence-based guidelines for management, treatment modalities vary and the risk for recurrence is questionable and not known.

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.

Haemangiomas in the urinary bladder: Two case reports

BACKGROUND

Urinary bladder haemangioma is a benign nonurothelial tumour that rarely occurs in paediatric and adolescent patients. Clinical and radiological examinations are not adequate for an accurate diagnosis. The purpose of this serial case report is to raise awareness of urinary bladder haemangioma and appropriate management.

CASE SUMMARY

We described two rare cases of urinary bladder haemangioma that were confirmed by histopathology followed by immunohistochemistry and reviewed the literature on the diagnosis and treatment of patients with this disease. The radical cystectomy was performed with open method surgery associated with an abdominal wall ostomy of the ileal outlet tract for case 1. Case 2 underwent a laparoscopic partial cystectomy. Postoperative pathology confirmed the diagnosis of urinary bladder haemangioma. Haematuria resolved postoperatively, and there was no evidence of tumour recurrence in 3 years follow-up for case 1. Postoperative urinary and pelvic ultrasonography showed no signs of recurrence in 3 mo follow-up for case 2.

CONCLUSION

Careful histopathological and immunohistochemical studies are required to establish the correct diagnosis. There is no “gold standard” treatment for urinary bladder haemangioma, and treatment options are varied for individuals with favourable follow-ups.

Bladder perivascular epithelioid cell neoplasm: The importance of immunohistochemistry in the diagnosis of an unusual neoplasm

Perivascular epithelioid cell neoplasms represent a group of uncommon mesenchymal tumours with as yet undiscovered benign counterpart. Although perivascular epithelioid cell neoplasms have been described arising in most organ systems as well as in soft tissue and bone, only a small number of perivascular epithelioid cell neoplasms have been reported in the bladder. To date, there is no agreed system for predicting the behaviour of these tumours. We describe a case of a perivascular epithelioid cell neoplasm of the bladder arising in a 57-year-old male and initially diagnosed on biopsy and present a review of the literature focussing on the pathological differential diagnosis and the importance of key histological features in conjunction with a broad immunohistochemical panel. This case report highlights the key features of bladder perivascular epithelioid cell neoplasms that distinguishes these rare neoplasms from other bladder lesions.

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.

Stage T1 bladder cancer: diagnostic criteria and pitfalls

Accurate pathological staging is crucial for patient management. Patients with T1 bladder cancer are at risk of recurrence, progression, and death of cancer. Recognition of early invasion (stage T1 disease) in urothelial carcinoma remains one of the most challenging areas in urological surgical pathology practice. A logical roadmap to T1 diagnosis would include careful evaluation of histological grade, stromal epithelial interface, characteristics of the invading epithelium, and the stroma associated responses. Tangential sectioning, crush and cautery artifacts, and associated inflammatory infiltrate are commonly encountered problems and the source of pitfalls. In this review, we outline diagnostic criteria, common pitfalls, and different histological patterns of invasion into the lamina propria. Current recommendations on reporting of biopsy and transurethral resection specimens, molecular biomarkers, clinical implications of T1 cancer diagnosis and recent developments on the T1 substaging are also discussed. Most T1 bladder cancer patients will benefit from conservative management after restaging transurethral resection of bladder and bacillus Calmette-Guérin maintenance. Patients with high risk features, such as concurrent urothelial carcinoma in situ, increased depth of invasion, lymphovascular invasion, and variant histology among others, should be considered for early cystectomy.

Bladder Leiomyoma with Synchronous Solitary Fibrous Tumor of the Pleura

Bladder leiomyomas (BLs) are extremely rare benign tumors of mesenchymal origin. The exact pathophysiological mechanisms that lead to their appearance remain unclear including hormonal disorders, chromosomal abnormalities, and fetal remnants in the bladder. They usually remain asymptomatic for a long period of time. Solitary fibrous tumors (SFTs) are also rare neoplasms of mesenchymal origin with malignant potential usually affecting the pleura. The pathogenesis of SFTs remains unclear. We report the case of a 28-year-old male presenting with SFT of the pleura and synchronous BL. The patient presented with persistent cough as a sole symptom. Computed tomography (CT) of the thorax revealed a pleural mass, which was surgically removed and proved to be a SFT. At an early follow-up, abdominal CT scan revealed a bladder wall mass that proved to be a BL. This is the first report of BL with synchronous SFT of the pleura. Synchronous BLs and SFTs may be incidental, but the coexistence of two mesenchymal tumors at different sites, in a young patient, may raise the suspicion of a new clinical syndrome that warrants further investigation.

The applicability and utility of immunohistochemical biomarkers in bladder pathology

Urinary bladder specimens are frequently encountered in the daily practice of surgical pathologists. The spectrum of pathologic entities encountered in bladder specimens is extraordinarily broad, and in some instances, immunohistochemical stains are used to help characterize challenging bladder lesions. Cost-effective biomarker selection tailored to the differential diagnosis facilitates an accurate diagnosis. This comprehensive review is prepared as a reference guide for the use of immunohistochemistry to categorize primary and secondary bladder neoplasms and to evaluate metastatic cancers for possible bladder origin.

Perivascular Epithelioid Cell Tumor of the Urinary Bladder: A Systematic Review

Perivascular epithelioid cell tumor (PEComa) of the urinary bladder is a rare neoplasm showing distinct melanocytic and smooth muscle differentiation. We aimed to review the clinicopathologic features of bladder PEComa using all the available cases in the literature, along with 2 new cases from our database. The patients included 15 females and 15 males with a mean age of 39.2 ± 15.3 years. Painless hematuria was the most common clinical presentation. The tumors were usually well circumscribed with a mean tumor size of 4.4 ± 2.7 cm. Bladder PEComas demonstrated nests, trabeculae, or sheets of epithelioid cells with intermixed spindled cells and numerous thin-walled vessels. Immunohistochemical studies showed that the tumors were positive for HMB45 (27/27), cathepsin (4/4), SMA (20/22), and caldesmon (3/3) and were negative for pan cytokeratin (0/18) and EMA (0/4). Molecular studies revealed that PEComa was associated with the TFE3 (n = 3) and EWSR1 (n = 1) gene rearrangements. Treatment included partial cystectomy (n = 18), transurethral resection (n = 8), and radical cystectomy (n = 4). Twenty patients had no evidence of disease during a mean follow-up time of 19.4 ± 17.2 months. Two patients had recurrence, and 1 patient died of metastatic disease. In conclusion, bladder PEComas demonstrate distinct morphologic and immunohistochemical features. Although most tumors follow a benign course, a small subset may develop metastasis and cause death.

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.

Bladder cavernous hemangioma after pelvic radiotherapy in a female patient: A case report and literature review

INTRODUCTION

Hemangiomas are benign tumor formations of capillaries and blood vessels which are commonly found in various organs. However they are extremely rare in urinary bladder accounting for only 0.6% of all urinary bladder tumors. The differentiating of these benign tumors from malignant neoplasms are important since they have extremely different prognostic features as well as therapeutic strategies. Here we reported a female patient diagnosed with bladder cavernous hemangioma (BCH) after recent pelvic radiotherapy for the cervical cancer and reviewed relevant literatures.

CASE PRESENTATION

We reported a case of 49 years old female patient with persistent painless hematuria for 12 days. Computed tomography revealed a small lesion on the superior wall of the urinary bladder with acute clot retention. Cystoscopy confirmed a solid papillary pedunculated mass with a measuring of 1.0 × 0.5 cm located on the superior posterior wall and surrounded by distended vessels. Transurethral resection of the mass was then performed and the pathological report indicated a cavernous hemangioma of the urinary bladder. In a one and half year follow-up, no tumor recurrence or bleeding was found.

CONCLUSIONS

The cavernous hemangioma in urinary bladder is rare and cystoscopic is a gold standard for diagnosis. Treatment options are vary for individuals and pathologic findings are vital for differentiating it from malignant potential tumors. A history of cancer related radiation therapy seems to be a risk factor for BCH.

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.

Practical Applications of Immunohistochemistry in the Diagnosis of Genitourinary Tumors

Context.—

Pathologic diagnosis of tumors in the genitourinary system can be challenging based on morphology alone, particularly when diagnostic material is limited, such as in core biopsies. Immunohistochemical stain can be a useful tool to aid in the diagnosis.

Objective.—

To provide an update on practical applications and interpretation of immunohistochemical stains in the diagnosis of tumors in prostate, kidney, bladder, and testis. We particularly focus on difficult differential diagnoses, providing our insights in frequently encountered challenging situations. Commonly used immunohistochemical panels are discussed.

Data Sources.—

Review of literature and our own experience.

Conclusion.—

Immunohistochemical stain is a valuable tool in the diagnosis of genitourinary tumors when appropriately used.

A novel fusion of HNRNPA1-ALK in inflammatory myofibroblastic tumor of urinary bladder

Here, we report an inflammatory myofibroblastic tumor (IMT) of the urinary bladder with a novel HNRNPA1-ALK fusion. To the best of our knowledge, this is the first case of a tumor with HNRNPA1-ALK fusion. A 42-year-old Japanese man underwent total cystectomy because of an invasive urinary bladder tumor. Grossly, the tumor had invaded the peribladder fat tissue. Histologically, it comprised spindle neoplastic cells with intermingled inflammatory cells. Immunohistochemically, it was positive for ALK, SMA, desmin, cytokeratin, and vimentin, consistent with the immunohistochemical characteristics of IMTs. Fluorescence in situ hybridization demonstrated an ALK split, and the presence of HNRNPA1-ALK was revealed by RNA sequencing. We identified a novel transcript fusion of exon 2 of HNRNPA1 and exon 18 of ALK, resulting in ALK protein overexpression. These findings provide useful information on the biology and tumorigenesis of IMTs, thus facilitating the development of molecular-targeted therapeutics.

Myopericytoma in urinary bladder: a case report

BACKGROUND

Myopericytoma is reported to occur mainly in the skin and superficial soft tissue of the extremities. In contrast, occurrence in the urinary bladder is extremely rare.

CASE PRESENTATION

We describe a 75-year-old Japanese man who developed a submucosal tumor at the right trigone of his bladder that led to interference with the discharge of right ureteral calculus. No invasive growth was observed by magnetic resonance imaging. Transurethral resection was successfully performed; histopathological analysis revealed perivascular proliferation of spindle-shaped to oval-shaped, cytologically bland tumor cells with eosinophilic cytoplasm. On immunohistochemical examination, the tumor cells were positive for alpha-smooth muscle actin, desmin, CD34 and h-caldesmon.

CONCLUSION

Cystoscopic and pathological findings were compatible with a diagnosis of myopericytoma of the urinary bladder.

Inflammatory Myofibroblastic Tumor of the Bladder: 2 Rare Cases Managed with Laparoscopic Partial Cystectomy

Two cases of inflammatory myofibroblastic tumor (IMT) of the bladder are reported here. Both patients were male and presented with macroscopic hematuria; in the first case terminal hematuria was associated with irritative voiding symptoms. The second case was a smoker with hematuria unresponsive to medical treatment and anemia. Clinical presentation, pathological features, treatment, and prognosis are discussed. Due to rarity of this pathological condition, there are no guidelines concerning treatment and follow-up. We present our follow-up scheme and highlight the use of laparoscopic partial cystectomy as a successful treatment approach.

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.

[Mesenchymal tumors of the urinary bladder]

Mesenchymal tumors and tumor-like lesions of the urinary bladder are rare. They encompass a heterogeneous group of reactive pseudosarcomatous tumor-like changes and benign neoplastic lesions as well as malignant neoplasms (sarcomas) with variable biological behavior. The well-known differential diagnostic difficulties related to these conditions are mainly due to their rarity and thus limited experience and familiarity with their histological features and due to the significant morphological overlap between fully benign reactive conditions and aggressive malignant neoplasms. The distinction between them may on occasion represent a real challenge and is associated with several pitfalls. This overview summarizes the clinicopathological and differential diagnostic aspects of the most important lesions and discuss their differential diagnosis in the light of current knowledge.

Successful treatment and follow-up of a case of recurrent pseudosarcomatous myofibroblastic proliferation

This report describes a case of recurrent pseudosarcomatous myofibroblastic proliferation (PMP) of the bladder with a satisfactory clinical course after a 3.5-year follow-up. There is a lack of reports of successful treatment experiences on recurrent PMP of the bladder in adults. For the primary lesion, a transurethral resection of the bladder tumor (TUR-BT) was performed; for the recurrent lesion, a combination regime of TUR-BT and intravesical mitomycin C proved effective treatment. The patient did not suffer local recurrence or distal metastasis during the 3.5-year follow-up. Our experience may serve as treatment reference to urologists who encounter similar cases.

Inflammatory myofibroblastic tumor of the bladder

We illustrate a case of an inflammatory myofibroblastic tumor (IMT) involving the bladder in a woman with dysuria and review the literature and differential diagnosis. Inflammatory myofibroblastic tumor, also referred to as pseudosarcomatous myofibroblastic proliferation, is a rare lesion that can arise in the genitourinary system and is characterized by a fascicular arrangement of myofibroblasts with admixed inflammatory cells and slitlike vessels. Urinary bladder IMT can be a diagnostic pitfall because its histologic features (brisk mitoses, invasion into muscularis propria, and prominent nucleoli) can mimic malignancy. The differential diagnosis of urinary bladder IMT includes sarcomatoid carcinoma and leiomyosarcoma. Diagnostic features such as bland nuclear chromatin, ganglion-like cells, pale eosinophilic cytoplasm with long processes, overexpression of anaplastic lymphoma kinase (immunohistochemistry or gene rearrangement studies), and the absence of atypical mitoses help distinguish IMT from its malignant mimics. Current controversies regarding postoperative spindle cell nodule and IMT are discussed.

Inflammatory myofibroblastic tumors of the urinary bladder: a systematic review

We systemically reviewed the literature on inflammatory myofibroblastic tumors (IMTs) of the urinary bladder and compared between anaplastic lymphoma kinase (ALK)-positive and ALK-negative IMTs. An extensive search of the literature was performed in Medline and Web of Science using the following terms: "inflammatory myofibrolastic tumor," "inflammatory pseudotumor," and "bladder." A manual search was also performed using the web-based search engine Google Scholar. Reference lists of the retrieved articles were reviewed for other relevant studies. Patients' and disease characteristics of each individual case were reviewed. Further analyses were performed to compare between ALK-positive and ALK-negative IMTs. Forty-one studies were identified, and 182 patients were included for review and subsequent analyses. Of the IMTs, 65% were ALK-positive. Local tumor recurrence rate was 4%, and no cases of distant metastases have been reported. Compared with ALK-negative IMTs, ALK-positive IMTs had a female predilection with a sex ratio (male:female) of 1:1.67 (P = .048). ALK-positive IMTs also appeared to occur in younger patients (P = .072). No significant differences were noted in terms of their clinical presentations and histologic features. On immunohistochemical staining, ALK-positive IMTs had more positive results for desmin (P = .042) and p53 (P = .05), and more negative results for clusterin (P = .003). In summary, ALK-positive IMTs of the urinary bladder had a female predilection, appeared to occur more frequently in younger patients, and had different immunohistochemical staining patterns when compared with ALK-negative IMTs. Regardless of its ALK status, IMT of the urinary bladder has a good prognosis after surgical resection.

Inflammatory Myofibroblastic Tumours of the Urinary Bladder: Multi-Centre 18-Year Experience

Objective: To review a series of inflammatory myofibroblastic tumours (IMTs) of the urinary bladder in 10 hospitals in Hong Kong. Methods: A database search in the pathology archives of 10 hospitals in Hong Kong from 1995 to 2013 was performed using the key words ‘inflammatory myofibroblastic tumour', ‘inflammatory pseudotumour' and ‘spindle cell lesion'. Patient characteristics, clinical features, histological features, immunohistochemical staining results and treatment outcomes were reviewed. Results: Nine cases of IMT of the urinary bladder were retrieved. The mean age was 45.4 ± 22.8 years (range 11-78). Eight patients (88.9%) presented with haematuria and 5 patients (55.6%) had anaemia with a mean haemoglobin level of 6.8 ± 1.3 g/dl. Histologically, the majority of patients (77.8%) had a compact spindle cell pattern. Anaplastic lymphoma kinase staining was positive in 75% of cases. During a mean follow-up period of 43.4 months (range 8-94), none of them developed any local recurrence or distant metastasis. Conclusions: A high index of suspicion of IMT should be maintained for young patients presenting with bleeding bladder tumours and significant anaemia. IMTs of the urinary bladder run a benign disease course, and good prognosis can be achieved after surgical resection.

An inflammatory myofibroblastic tumor exhibiting immunoreactivity to KIT: a case report focusing on a diagnostic pitfall

Inflammatory myofibroblastic tumors (IMTs) and gastrointestinal stromal tumors (GISTs) are both spindle cell tumors, and occur rarely in the wall of the urinary bladder. In general, immunostaining allows differentiation of IMTs and GISTs. Most IMTs are positive for anaplastic lymphoma kinase (ALK) and negative for KIT, whereas most GISTs are ALK-negative and KIT-positive. Here, we describe a case of a spindle cell tumor in the wall of the urinary bladder. The spindle cells were positive for both ALK and KIT, and it was thus difficult to determine whether the tumor was an IMT or a GIST. We eventually diagnosed an IMT, because ALK gene rearrangement was confirmed by fluorescent in-situ hybridization. Cytoplasmic staining for KIT and the absence of other GIST markers, including DOG1 and platelet-derived growth factor α, indicated that the tumor was not a GIST. Therefore, IMTs should be included in the differential diagnosis of spindle cell tumors, even those that are KIT-positive.

Postoperative spindle cell nodule of the bladder: A case report and review of the literature

Postoperative spindle cell nodule (PSCN) of the bladder is a rare condition. It is a type of benign lesion frequently misdiagnosed as sarcomatoid carcinoma on the basis of similar cell morphology. The present report describes a tumor affecting a 71-year-old male who had undergone three transurethral resections. Pathological results suggested a diagnosis of sarcomatoid carcinoma, and therefore a radical cystectomy was performed. However, the tumor was later identified as a PSCN. In order to prevent such misdiagnosis, this study reviews relevant articles concerning postoperative spindle cell nodules of the bladder and compares PSCN and sarcomatoid carcinomas to identify specific characteristics of PSCN. Finally, the report emphasizes the importance of careful pathological examination in rare cases such as PSCN and sarcomatoid carcinoma.

Sarcomatoid variant of urothelial carcinoma (carcinosarcoma, spindle cell carcinoma): a review of the literature

Background. Sarcomatoid variant of urothelial carcinoma (SVUC) was added to the WHO classification in 2004. Aims. To review the literature. Materials and Method. Various internet databases were used. Result. SVUCs are rare biphasic malignant neoplasms exhibiting morphologic/immunohistochemical evidence of epithelial and mesenchymal differentiation with the presence or absence of heterologous elements. Some cases of SVUC have been associated with radiation therapy and cyclophosphamide treatment. Patients' ages range from 50 to 77 years (mean age 66). Patients tend to be younger and they more commonly presented with high-grade histology and advanced stage disease, in comparison with patients who had conventional urothelial carcinoma (CUC). Results of molecular/genetic studies strongly argue for a common monoclonal cell origin of both the epithelial and mesenchymal components in SUVC. The cancer specific survival of SVUC is poor in comparison with CUC. Radical surgical excision and chemoradiation may be associated with improved prognosis; chemoradiation as an organ preserving alternative to radical excision may be associated with improved outcome. There is no consensus opinion on the best treatment modalities for SUVC. Conclusions. SVUC is rare and is associated with inferior outcome compared with CUC. A multicentre trial of various treatment options is required. Cases of SVUC should be reported.

Low-grade myofibroblastic proliferations of the urinary bladder

CONTEXT

Myofibroblastic proliferations of the urinary bladder, which share some similarities with nodular fasciitis, were first reported in 1980. Since then, they have had several designations, the most frequently used being inflammatory myofibroblastic tumor. Based on both histopathologic and prognostic grounds, some authors prefer the term pseudosarcomatous myofibroblastic proliferation, at least for some of the proliferations. These same scientists also assimilate the so-called postoperative spindle cell nodules with the pseudosarcomatous myofibroblastic proliferations. Little is known about these low-grade myofibroblastic proliferations.

OBJECTIVES

To review the literature about low-grade myofibroblastic proliferations occurring in the urinary bladder.

DATA SOURCES

Textbooks and literature review. We obtained most of the clinicopathologic peculiarities from a patient population composed of the most-relevant, previously reported cases.

CONCLUSIONS

The low-grade myofibroblastic proliferations of the urinary bladder are rare lesions affecting males more often than they do females. The most-common signs and symptoms are hematuria and dysuria. Histopathologically, they are spindle cell proliferations in a loose myxoid stroma, even though compact proliferations or hypocellular fibrous patterns can be found. Immunohistochemistry is quite nonspecific, except for ALK-1 positivity (20%-89%). Fluorescence in situ hybridization has demonstrated clonal genetic aberrations involving the ALK gene in 50% to 60% of cases. After surgery, only 6% of patients experience local recurrence, without metastases or deaths from the disease. Malignant transformation has been reported exceptionally. These myofibroblastic proliferations are probably part of a continuum with, at one end, benign pseudosarcomatous proliferations and, at the opposite end, more-aggressive lesions. Because of the frequently indolent clinical course, aggressive treatment would be unjustified.

An unusual cause of urinary retention in a young female: a case report

Inflammatory myofibroblastic tumors are commonly seen in young adults and adolescents and commonly present with painless hematuria. We report a case of a 38-year-old woman who presented to us with urinary retention due to a prolapsing tumor mass from the urethra, which was discovered to be an inflammatory myofibroblastic tumor arising from the bladder base and involving the bladder neck. The patient underwent a successful transurethral resection of the tumor and at 6-month follow-up was continent and symptom-free.

Mesenchymal tumours of the bladder and prostate: an update

Mesenchymal tumours of the urinary bladder and prostate are infrequent neoplasms. The body of literature is growing with isolated case reports and short series, and the majority of cases are benign neoplasms. Other than stromal tumour of uncertain malignant potential and prostatic stromal sarcoma, both neoplasms derived from the specific prostatic stroma, the mesenchymal neoplasms in these locations are identical to their counterparts seen in other organs. However, the limited amount of tissue generated by biopsy and rarity of mesenchymal lesions in these sites create unique diagnostic difficulties, while correct classification of the neoplasm often bears significant impact on prognosis and therapeutic strategy. In this review we summarise the diagnostic features, focus on the differential diagnosis, and highlight the potential diagnostic pitfalls of mesenchymal tumours of the bladder and prostate.

Infantile neuroblastoma of the urinary bladder detected by hematuria

Malignant tumors of the urinary bladder in infants are extremely rare. Rhabdomyosarcoma is the most likely tumor in this site, whereas neuroblastoma of the urinary bladder is exceedingly uncommon and is not listed as a differential diagnosis for tumors of this site. We present a case of neuroblastoma arising from the dome of the bladder wall, detected by hematuria. Only six cases of neuroblastoma originating from the bladder, including the present case have been reported. Of the cases, five arose from the dome of the bladder wall. In this report, the differential diagnosis of bladder tumors in children is discussed. A diagnosis of neuroblastoma should be taken into consideration, especially in the case of tumors arising from the dome of the bladder wall despite an uncommon location.

Bovine papillomavirus type 2 infection and a series of mesenchymal tumors of the urinary bladder in cattle

This report describes the histopathology of two hundred and fifty-three mesenchymal tumors of the urinary bladder in cattle grazing on lands rich in bracken fern. Approximately 80% were hemangiomas and angiosarcomas. Hemangioma (capillary, cavernous, and large vessels) was the most frequent mesenchymal tumor and was more common than angiosarcoma. Although the appearance of endothelial cells can vary remarkably, epithelioid angiosarcomas, often containing multinucleated cells, were the most frequent malignant vascular tumors. Hemangiopericytoma and tumors of muscle and soft connective tissue origin, alone and/or in association with tumor-like lesions, were less frequently seen. Furthermore, forty-five cases of intravascular papillary endothelial hyperplasia (IPEH), a lesion not previously reported in the urinary bladder of cattle, were also described. Bovine papillomavirus type-2 DNA was amplified in tumor samples. Forty vascular tumors were investigated by dual-labeling immunofluorescence, and, for the first time, a coexpression of E5 and platelet-derived growth factor β receptor (PDGFβR) was shown to occur. The results show that the BPV-2 E5 oncoprotein binds to the activated form of the PDGFβ receptor thus playing an important role in mesenchymal as well as epithelial carcinogenesis of the urinary bladder. Furthermore, these findings demonstrate that BPV-2 infects both epithelial and mesenchymal cells.

A case of concomitant occurrence of solitary fibrous tumor and urothelial high-grade invasive carcinoma of the urinary bladder

Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm, most commonly arising from the pleura. It has also been recently described to occur in extrapleural sites. To our knowledge, only 16 cases of SFT have been reported in the urinary bladder to date. We report the clinicopathological features of a vesical SFT occurring in a 60-year-old man who presented a concomitant invasive high-grade urothelial cell carcinoma. No similar association has been found in the accessible literature. The morphologic and immunohistochemical clues leading to the correct diagnosis of SFT have been correlated with the data of the literature, and the differential diagnosis is briefly discussed.

Pseudosarcomatous myofibroblastic tumour of the urinary bladder: a case report

A pseudosarcomatous myofibroblastic proliferation is an unusual and a rare benign lesion which arises from the bladder submucosal stroma and is easily mistaken for a malignant neoplasm, clinically, radiologically and histologically. By definition, the tumour is composed of a dominant spindle cell proliferation with a variable inflammatory component. These spindle cells are now known to be myofibroblasts and this is the reason for the current designation for this disease. The term 'inflammatory' may not be applicable to all the tumours, since some investigators have demonstrated the presence of chromosomal abnormalities and have documented cases which showed recurrence, thus supporting the theory that at least some of these tumours were true neoplasms.Non-epithelial tumours account for 2-5% of all the primary urinary bladder neoplasms, with the most common types being rhabdomyosarcoma in patients under the age of 10 years and leiomyosarcoma in adults. A pseudosarcomatous myofibroblastic tumour is a nonepithelial lesion that follows a benign indolent course and a conservative management has been reported as the treatment of choice. Herein, we are reporting a case of a pseudosarcomatous myofibroblastic tumour which was mistaken for a sarcoma clinically and radiologically and which was proved as a pseudosarcomatous inflammatory myofibroblastic tumour by histopathology and immunohistochemistry.

Urinary bladder pyogenic granuloma: a case report

Introduction

Although more than 100 cases of hemangioma of the urinary bladder have been reported, capillary-type hemangiomas of the bladder are rare. Pyogenic granulomas, which are common tumor-like vascular lesions of the skin and oral mucous membranes, reveal histopathological findings similar to capillary-type hemangiomas and are differentiated from ordinary hemangiomas by clinical features and etiologic factors. Little is known regarding the occurrence of pyogenic granulomas in the urinary bladder.

Case presentation

We present the case of a 78-year-old Japanese man who had developed a hemangiomatous lesion in his bladder which led to acute clot retention. He had a recent history of chemotherapy for pancreatic cancer. A solitary pedunculated mass measuring 1.2 cm was observed in the bladder. Histopathological analysis of the resected mass revealed marked lobular capillary proliferation with surface erosions.

Conclusion

Cystoscopic and pathologic findings in addition to possible predisposing factors supported a diagnosis of pyogenic granuloma of the urinary bladder.

Postoperative spindle cell nodule after thyroidectomy: a case mimicking recurrence with anaplastic transformation of thyroid cancer

BACKGROUND

Here, we report a case of a postoperative spindle cell nodule that mimicked recurrence with anaplastic transformation after thyroidectomy.

METHODS

The course of the disease is described. The mass was studied morphologically and immunohistochemically.

RESULTS

A 31-year-old woman underwent total thyroidectomy for papillary thyroid carcinoma. A mass suspected of recurrence was found 14 months later and caused dysphagia and dyspnea. An (18)F-fluorodeoxyglucose positron emission tomographic ((18)F-FDG-PET) scan showed a lesion with high uptake; however, a fine-needle aspiration biopsy (FNAB) was inconsistent with recurrent cancer. The mass was resected and was composed of elongated spindle cells, with eosinophilic cytoplasm within a myxoid background. Immunohistochemical staining was strongly positive for vimentin, focally positive for smooth muscle actin, desmin, and p53, and negative for cytokeratin AE1/AE3, Cam5.2, epithelial membrane antigen (EMA), and anaplastic lymphoma kinase (ALK-1).

CONCLUSION

Although postoperative spindle cell nodules are rare after thyroid surgery, it should be considered in the differential diagnosis for recurrent masses at the operative site.

Comparison of different adjuvant radiotherapy approaches in childhood bladder/prostate rhabdomyosarcoma treated with conservative surgery

BACKGROUND AND PURPOSE

Multimodality treatment approaches provide high local control and satisfying overall survival (OS) for children with localized bladder and/or prostate rhabdomyosarcoma (BP-RMS). However, current strategies including surgery and conventional radiotherapy are compromised by high rates of long-term genitourinary adverse effects. Therefore, a planning study combining organ preserving surgery with three different innovative adjuvant radiotherapy approaches was performed.

PATIENTS AND METHODS

A case of a 21-month-old boy with BP-RMS treated with polychemotherapy according to the CWS 2002-P protocol, prostatectomy, partial cystectomy, and adjuvant high dose rate brachytherapy (HDR-BT) was used to perform a planning study comparing HDR-BT with intensity-modulated radiotherapy (IMRT) and intensity-modulated proton therapy (IMPT) planning.

RESULTS

All modalities provide good coverage of the target volume and spare critical normal tissues. Rectum doses could be reduced by 2/3 using IMPT and by 1/3 using BT compared to IMRT. In terms of sparing the pelvis growth plates, BT and IMPT are also superior to IMRT.

CONCLUSION

All modalities provide good sparing of normal tissue. BT and IMPT are superior to IMRT with regard to doses on rectum and growth plates. BT is equivalent to IMPT in adequately selected tumors.

Clinical utility of immunohistochemistry in the diagnoses of urinary bladder neoplasia

Urothelial carcinomas demonstrate diverse morphologic and immunologic features that frequently lead to diagnostic challenges. Recent advances have identified a number of immunohistochemical stains that, when used in the context of a panel, can be a valuable tool in properly classifying primary urothelial carcinoma and carcinomas secondarily involving the urinary bladder. In addition, new biomarkers prove helpful in the staging of bladder carcinoma. In this article, we review the clinical utility of immunohistochemistry in a series of diagnostic scenarios, including flat urothelial lesions with atypia, rare variants of urothelial carcinoma, primary adenocarcinoma versus secondary colorectal tumors, distinguishing prostate from urothelial carcinoma, and the utility of smoothelin in staging bladder carcinoma. Emphasis is placed on panels of commonly used biomarkers to establish diagnoses.

Leiomyoma of the urinary bladder: a series of nine cases and review of the literature

OBJECTIVES

To present our experience with 9 cases of bladder leiomyomas and a review of the relevant published data.

METHODS

During a 13-year period, 9 patients were treated for bladder leiomyoma. Their medical records were retrospectively reviewed, and data, including age, sex, symptoms, tumor size and location, cystoscopy results, radiologic examination findings, method of extirpation, pathology slides, and follow-up results, were analyzed.

RESULTS

All 9 patients were women, with a mean age of 43.6 years (range 24-65). Of the 9 patients, 5 reported urinary symptoms, 1 presented with gross hematuria, and 3 were asymptomatic. The mean tumor size was 4.2 cm (range 2.4-7). The tumor size was larger in symptomatic patients than in the asymptomatic patients. All tumors were endovesical lesions; 1 patient had a concomitant extravesical tumor. Transurethral resection was performed in 6 patients, partial cystectomy in 2, and enucleation in 1. Microscopically, the tumors were composed of bland, spindle-shaped cells. Recurrence developed in 2 patients. Both patients underwent repeat resection, and no additional recurrence developed.

CONCLUSIONS

Leiomyoma of the bladder is rare and occurs predominantly in women. The size, rather than the location, of the tumor appeared to be more closely related to the occurrence of symptoms. Surgical excision is the standard approach to diagnosis and treatment.

[Pseudosarcomatous myofibroblastic proliferation of the bladder]

Myofibroblastic proliferations of the bladder in adults are unusual lesions with a benign course. These proliferations, whether spontaneous or secondary to instrumentation, have identical morphology and behaviour. Histologically, similar lesions have been reported in the literature using different names, such as inflammatory pseudotumour, pseudosarcomatous fibromyxoid tumour, nodular fasciitis, postoperative spindle cell nodule... Recently, some authors proposed that these lesions are similar enough to be considered the same entity, designated as "pseudosarcomatous myofibroblastic proliferation" and insisted on the necessity to distinguish them from the inflammatory myofibroblastic tumour of the childhood. The latter, recently recognized as tumour, has a malignant potential and is capable of giving metastases. We describe the case of a 17-year-old man who presented a vesical mass. The histopathological study concluded to a pseudosarcomatous myofibroblastic proliferation. We discuss, through a literature review, the relationship of this lesion with inflammatory myofibroblastic tumour and its main differential diagnoses.