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Isolated Pure Malignant Rhabdoid Tumor (MRT) of the Bladder: Case Report and Lessons Learned
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Isolated pure malignant rhabdoid tumor (MRT) of the bladder: case report and lessons learned Sarah L. Hecht , Jonathan P. Walker , Amy L. Treece , Nicholas G. Cost PII: DOI: Reference:
S0090-4295(19)30974-4 https://doi.org/10.1016/j.urology.2019.10.023 URL 21846
To appear in:
Urology
Received date: Revised date: Accepted date:
1 August 2019 27 October 2019 31 October 2019
Please cite this article as: Sarah L. Hecht , Jonathan P. Walker , Amy L. Treece , Nicholas G. Cost , Isolated pure malignant rhabdoid tumor (MRT) of the bladder: case report and lessons learned, Urology (2019), doi: https://doi.org/10.1016/j.urology.2019.10.023
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier Inc.
Isolated pure malignant rhabdoid tumor (MRT) of the bladder: case report and lessons learned
Sarah L. Hechta, Jonathan P. Walkera, Amy L. Treeceb, Nicholas G. Costa a
Department of Surgery, Division of Urology, University of Colorado, Aurora, CO
b
Children's Hospital of Colorado, Department of Pathology, Aurora, CO
Corresponding author: Sarah L. Hecht, MD Pediatric Urology Fellow Children’s Hospital of Colorado Department of Urology 13123 East 16th Avenue B-463 Aurora, CO 80045 [email protected] Tel: 720-777-3926 Fax: 720-777-7370
Keywords: Rhabdoid, bladder, pediatric oncology, pelvic tumor
Financial disclosures: None
Abstract: Pediatric extrarenal malignant rhabdoid tumors (MRTs) are rare, aggressive tumors with a poor prognosis (20% 5-year survival). There are currently fewer than 10 published case reports of primary MRT of the bladder. We report the case of an 18 month-old female with an isolated MRT of the bladder which was initially misdiagnosed as an inflammatory myofibroblastic tumor on biopsy. We review the history, tumor biology, histology, and current management of extrarenal MRT, along with lessons learned from the difficulty with the patient’s initial diagnosis.
Case-Presentation: An 18-month-old previously healthy female presented with several weeks of abdominal pain, urinary frequency, and weight loss. She was diagnosed with a urinary tract infection. Subsequent renal-bladder ultrasound demonstrated a 5.4x3.9x4.4cm bladder mass with internal flow and overlying calcifications (Figure 1). Physical exam was notable for a palpable abdominal mass and no protruding urogenital mass. Staging CT scan re-demonstrated a bladder mass arising from the left posterolateral bladder. There was no hydronephrosis or metastatic disease. She subsequently underwent transurethral biopsy. Intraoperatively, the mass appeared broadbased and sessile. The left ureteral orifice was spared. Frozen section pathology was indeterminate. Final pathology based on nearly 1cm3 of aggregate specimen was most consistent with inflammatory myofibroblastic tumor (IMT). Based on this diagnosis, steroid and NSAID therapy was initiated with plans for surgical resection of residual tumor in 6 weeks. Her symptoms failed to improve, and a repeat ultrasound 2 weeks after her biopsy showed tumor growth and new bilateral hydronephrosis. Given her persistent symptoms and failure to respond to steroids, the decision was made to proceed with partial cystectomy. Repeat cystoscopy
confirmed growth of the tumor, which now occluded the left ureteral orifice and abutted the bladder neck. She underwent partial cystectomy, bladder neck reconstruction, left ureteral reimplant, and bilateral pelvic lymph node dissection. The bladder was thickened and fibrotic (Figure 2). Bilateral ureteral stents, a Foley catheter, and a pelvic drain were left. Steroids were weaned. Postoperatively, she developed a persistent urine leak from the bladder neck requiring prolonged urethral catheterization and perivesical drainage. The leak eventually sealed, and cystogram at the time of stent removal revealed a 90ml bladder capacity. Final pathology unexpectedly revealed pure malignant rhabdoid tumor (MRT), 7x5.8x5cm. There was a focal (<3mm) positive margin at the posterior aspect of the resection. Lymph nodes were negative for metastatic disease. Based on the malignant pathology, positive margin, and persistent urine leak in the setting of recent steroids and upcoming chemotherapy, the option of completion cystectomy and cutaneous urinary diversion was presented to a multidisciplinary tumor board. Ultimately, the family’s preference was to avoid further major surgery. The tumor board agreed with this course of action given the size and location of the positive margin and the greater likelihood of metastatic disease over local recurrence. A Mediport was placed. The initial treatment plan was per a published protocol(1). Family declined autologous stem cell transplant, and her plan was revised to 4 cycles of VDC (vincristine, dactinomycin, cyclophosphamide), 4 cycles of ICE (ifosfamide, carboplatin, etoposide), followed by 4 weeks of pelvic radiotherapy due to her positive margin. Surveillance imaging 6 weeks following completion of radiation therapy shows no evidence of disease.
Discussion: MRTs of the kidney were originally described as highly aggressive variants of Wilms tumor and were included in treatment protocols of the National Wilms Tumor Study(2), While
MRTs are now recognized as a distinct entity, a uniform treatment strategy is lacking(3). Surgical excision and chemotherapy are the cornerstones of therapy. The benefit of radiation is unclear, and may be confounded by age as radiation is generally avoided in young patients(4). Outcomes are poor, with tumor stage and age at presentation (younger is worse) being the only identifiable prognostic factors(5–7). The most robust analysis to date of extrarenal, non-CNS MRTs pooled several series to study 49 patients, and found a median age at presentation of 7.3yrs with a 20% 5-year survival rate(8). There are fewer than 10 published case reports of isolated pure MRT of the bladder. Of these, four report survival greater than 1 year, all of whom had complete tumor resection and chemotherapy(9–12),. MRTs are associated with loss of SMARCB1, a tumor suppressor gene that encodes the protein INI1 (integrase interactor 1, also called BAF47 or SNF5). Loss of INI1 expression is nearly ubiquitous among rhabdoid tumors, which is useful to confirm the diagnosis as rhabdoid tumors can be histologically heterogeneous. Heterogeneity in the histologic spectrum of MRTs as well as inflammation in the biopsy led to the difficulty with the initial diagnosis in our case. The histopathology of the biopsy specimen did not exhibit typical features of MRT (Figure 3A), instead showing fibrotic tissue with dense cellular proliferation arranged in a fascicular pattern. Mitotic figures were rare. There was lymphocytic infiltration with scattered plasma cells, eosinophils, and neutrophils, in keeping with the inflammatory infiltrate that can be seen in IMT. Immunostaining was consistent with, albeit nonspecific for, ALK-negative IMT. By contrast, final tumor pathology showed marked nuclear pleomorphism, prominent nucleoli, necrosis with overlying dystrophic calcification, and a high mitotic rate, prompting staining for INI1. Loss of INI1 established the diagnosis of MRT (Figure 3B-C). In the resection specimen, it was clear the inflammatory infiltrate was confined to the superficial portion of the tumor and represented a reactive process.
Concerns surrounding misdiagnosis are complex and include patient harm, ethical disclosure, medicolegal risk, and systemic burdens of medical error(13,14). Our approach was to first to assess and mitigate harm to the patient, and secondly to support the family. In this case, it is unclear whether a delay in diagnosis was clinically harmful. Had the initial biopsy revealed MRT, the patient would have undergone radical cystectomy and cutaneous diversion. The positive tumor margin was posterior, not at the bladder edge, thus radical cystectomy likely would not have averted this margin and subsequent radiation therapy. In the unfortunate event of relapse, we cannot conclude that radical cystectomy would have been preventive given the globally poor disease prognosis. Regarding the physician-family relationship, our approach is to provide support through knowledge, availability, and a clear plan. While we cannot promise a good outcome, we can promise to disclose all information (and be honest when the answer is “I don’t know,”) to assure families they are never alone (we choose to share the attending physician’s cell phone number with our cancer patients), and to always have a next step in place. In our experience, this approach aligns the physician and the family under stressful circumstances which could otherwise lead to a contentious and counterproductive partnership. Moreover, as physicians we support each other, recognizing that there is intrinsic imperfection in all that we do. We share our experience to contribute to the scarce literature on pure MRT of the bladder, and to pass on lessons learned from the initial difficulty with diagnosis. Non-diagnostic bladder biopsy in the setting of bladder MRT has been reported, but unlike in this case, was secondary to inadequate tissue sampling(15). We recommend intraoperative communication with pathology to confirm that adequate tissue has been obtained even when not requesting frozen section for preliminary diagnosis. Furthermore, we advocate for operative lymph node sampling for all solid tumors given the minimal morbidity and potential prognostic and oncologic
benefit. Lastly, our practice has changed to include INI1 immunostaining for all ambiguous soft tissue malignancies.
Conclusion: Extrarenal, extracranial MRT is a rare entity with a poor prognosis. Its rarity and heterogeneity can complicate the diagnosis. Loss of INI1 expression is nearly ubiquitous, and INI1 staining should be considered in all solid tumors when histopathologic diagnosis is ambiguous. Alignment with the family and mutual support among healthcare team members has been central to our approach to all patients who receive bad news.
1. Venkatramani R, Shoureshi P, Malvar J, Zhou S, Mascarenhas L. High dose alkylator therapy for extracranial malignant rhabdoid tumors in children: Malignant Rhabdoid Tumor. Pediatr Blood Cancer. 2014 Aug;61(8):1357–61. 2. Beckwith JB, Palmer NF. Histopathology and prognosis of Wilms tumors: results from the First National Wilms’ Tumor Study. Cancer. 1978 May;41(5):1937–48. 3. Haas JE, Palmer NF, Weinberg AG, Beckwith JB. Ultrastructure of malignant rhabdoid tumor of the kidney: A distinctive renal tumor of children. Hum Pathol. 1981 Jul 1;12(7):646–57. 4. Morgenstern DA, Gibson S, Brown T, Sebire NJ, Anderson J. Clinical and pathological features of paediatric malignant rhabdoid tumours. Pediatr Blood Cancer. 2010 Jan;54(1):29–34. 5. Tomlinson GE, Breslow NE, Dome J, Guthrie KA, Norkool P, Li S, et al. Rhabdoid tumor of the kidney in the National Wilms’ Tumor Study: age at diagnosis as a prognostic factor. J Clin Oncol Off J Am Soc Clin Oncol. 2005 Oct 20;23(30):7641–5. 6. Reinhard H, Reinert J, Beier R, Furtwängler R, Alkasser M, Rutkowski S, et al. Rhabdoid tumors in children: prognostic factors in 70 patients diagnosed in Germany. Oncol Rep. 2008 Mar;19(3):819–23. 7. Islam M, Saltzman AF, Amini A, Carrasco A, Cost NG. Factors Influencing Overall Survival of Children, Adolescents, and Young Adults With High-risk Renal Tumors. Urology. 2018 Oct 1;120:222–30. 8. Oda Y, Tsuneyoshi M. Extrarenal rhabdoid tumors of soft tissue: clinicopathological and molecular genetic review and distinction from other soft-tissue sarcomas with rhabdoid features. Pathol Int. 2006 Jun;56(6):287–95. 9. Duvdevani M, Nass D, Neumann Y, Leibovitch I, Ramon J, Mor Y. Pure rhabdoid tumor of the bladder. J Urol. 2001 Dec;166(6):2337. 10. Chang JH, Dikranian AH, Johnston WH, Storch SK, Hurwitz RS. Malignant extrarenal rhabdoid tumor of the bladder: 9-year survival after chemotherapy and partial cystectomy. J Urol. 2004 Feb;171(2 Pt 1):820–1. 11. Warren KS, Oxley J, Koupparis A. Pure malignant rhabdoid tumour of the bladder. Can Urol Assoc J. 2014;8(3–4):E260–2. 12. Hoare D, Kiddoo D, Stryker T. An Antenatally Detected Pure Malignant Rhabdoid Tumor of the Bladder. Urology. 2019 Jan 1;123:221–3. 13. Wu AW, Cavanaugh TA, McPhee SJ, Lo B, Micco GP. To tell the truth: Ethical and practical issues in disclosing medical mistakes to patients. J Gen Intern Med. 1997 Dec;12(12):770–5. 14. Weingart SN, McL Wilson R, Gibberd RW, Harrison B. Epidemiology of medical error. West J Med. 2000 Jun;172(6):390–3. 15. Savage N, Linn D, McDonough C, Donohoe JM, Franco A, Reuter V, et al. Molecularly confirmed primary malignant rhabdoid tumor of the urinary bladder: implications of accurate diagnosis. Ann Diagn Pathol. 2012 Dec;16(6):504–7.
Figure 1: (A) Bladder ultrasound demonstrating an intravesical mass. (B) The mass and overlying calcifications are re-demonstrated on staging CT scan.
Figure 2: Gross images of the specimen. (A) Intact, endophytic tumor with overlying calcifications. The tumor measured 7.0 x 5.8 x 5.0cm. Note the thickened bladder wall (white arrow). (B) Bisected tumor.
Figure 3: (A) Slide from the initial transurethral biopsy, initially read as most consistent with inflammatory myofibroblastic tumor. (B) Slide from the final tumor resection shows typical findings of rhabdoid tumor including vesicular and eccentric nuclei, prominent nucleoli, and a high mitotic rate. (C) INI1 immunohistochemistry stain shows diffuse loss of INI1 expression in tumor nuclei, with appropriate staining of intra-tumoral endothelial cells serving as the internal control
Isolated pure malignant rhabdoid tumor (MRT) of the bladder: case report and lessons learned Sarah L. Hecht , Jonathan P. Walker , Amy L. Treece , Nicholas G. Cost PII: DOI: Reference:
S0090-4295(19)30974-4 https://doi.org/10.1016/j.urology.2019.10.023 URL 21846
To appear in:
Urology
Received date: Revised date: Accepted date:
1 August 2019 27 October 2019 31 October 2019
Please cite this article as: Sarah L. Hecht , Jonathan P. Walker , Amy L. Treece , Nicholas G. Cost , Isolated pure malignant rhabdoid tumor (MRT) of the bladder: case report and lessons learned, Urology (2019), doi: https://doi.org/10.1016/j.urology.2019.10.023
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier Inc.
Isolated pure malignant rhabdoid tumor (MRT) of the bladder: case report and lessons learned
Sarah L. Hechta, Jonathan P. Walkera, Amy L. Treeceb, Nicholas G. Costa a
Department of Surgery, Division of Urology, University of Colorado, Aurora, CO
b
Children's Hospital of Colorado, Department of Pathology, Aurora, CO
Corresponding author: Sarah L. Hecht, MD Pediatric Urology Fellow Children’s Hospital of Colorado Department of Urology 13123 East 16th Avenue B-463 Aurora, CO 80045 [email protected] Tel: 720-777-3926 Fax: 720-777-7370
Keywords: Rhabdoid, bladder, pediatric oncology, pelvic tumor
Financial disclosures: None
Abstract: Pediatric extrarenal malignant rhabdoid tumors (MRTs) are rare, aggressive tumors with a poor prognosis (20% 5-year survival). There are currently fewer than 10 published case reports of primary MRT of the bladder. We report the case of an 18 month-old female with an isolated MRT of the bladder which was initially misdiagnosed as an inflammatory myofibroblastic tumor on biopsy. We review the history, tumor biology, histology, and current management of extrarenal MRT, along with lessons learned from the difficulty with the patient’s initial diagnosis.
Case-Presentation: An 18-month-old previously healthy female presented with several weeks of abdominal pain, urinary frequency, and weight loss. She was diagnosed with a urinary tract infection. Subsequent renal-bladder ultrasound demonstrated a 5.4x3.9x4.4cm bladder mass with internal flow and overlying calcifications (Figure 1). Physical exam was notable for a palpable abdominal mass and no protruding urogenital mass. Staging CT scan re-demonstrated a bladder mass arising from the left posterolateral bladder. There was no hydronephrosis or metastatic disease. She subsequently underwent transurethral biopsy. Intraoperatively, the mass appeared broadbased and sessile. The left ureteral orifice was spared. Frozen section pathology was indeterminate. Final pathology based on nearly 1cm3 of aggregate specimen was most consistent with inflammatory myofibroblastic tumor (IMT). Based on this diagnosis, steroid and NSAID therapy was initiated with plans for surgical resection of residual tumor in 6 weeks. Her symptoms failed to improve, and a repeat ultrasound 2 weeks after her biopsy showed tumor growth and new bilateral hydronephrosis. Given her persistent symptoms and failure to respond to steroids, the decision was made to proceed with partial cystectomy. Repeat cystoscopy
confirmed growth of the tumor, which now occluded the left ureteral orifice and abutted the bladder neck. She underwent partial cystectomy, bladder neck reconstruction, left ureteral reimplant, and bilateral pelvic lymph node dissection. The bladder was thickened and fibrotic (Figure 2). Bilateral ureteral stents, a Foley catheter, and a pelvic drain were left. Steroids were weaned. Postoperatively, she developed a persistent urine leak from the bladder neck requiring prolonged urethral catheterization and perivesical drainage. The leak eventually sealed, and cystogram at the time of stent removal revealed a 90ml bladder capacity. Final pathology unexpectedly revealed pure malignant rhabdoid tumor (MRT), 7x5.8x5cm. There was a focal (<3mm) positive margin at the posterior aspect of the resection. Lymph nodes were negative for metastatic disease. Based on the malignant pathology, positive margin, and persistent urine leak in the setting of recent steroids and upcoming chemotherapy, the option of completion cystectomy and cutaneous urinary diversion was presented to a multidisciplinary tumor board. Ultimately, the family’s preference was to avoid further major surgery. The tumor board agreed with this course of action given the size and location of the positive margin and the greater likelihood of metastatic disease over local recurrence. A Mediport was placed. The initial treatment plan was per a published protocol(1). Family declined autologous stem cell transplant, and her plan was revised to 4 cycles of VDC (vincristine, dactinomycin, cyclophosphamide), 4 cycles of ICE (ifosfamide, carboplatin, etoposide), followed by 4 weeks of pelvic radiotherapy due to her positive margin. Surveillance imaging 6 weeks following completion of radiation therapy shows no evidence of disease.
Discussion: MRTs of the kidney were originally described as highly aggressive variants of Wilms tumor and were included in treatment protocols of the National Wilms Tumor Study(2), While
MRTs are now recognized as a distinct entity, a uniform treatment strategy is lacking(3). Surgical excision and chemotherapy are the cornerstones of therapy. The benefit of radiation is unclear, and may be confounded by age as radiation is generally avoided in young patients(4). Outcomes are poor, with tumor stage and age at presentation (younger is worse) being the only identifiable prognostic factors(5–7). The most robust analysis to date of extrarenal, non-CNS MRTs pooled several series to study 49 patients, and found a median age at presentation of 7.3yrs with a 20% 5-year survival rate(8). There are fewer than 10 published case reports of isolated pure MRT of the bladder. Of these, four report survival greater than 1 year, all of whom had complete tumor resection and chemotherapy(9–12),. MRTs are associated with loss of SMARCB1, a tumor suppressor gene that encodes the protein INI1 (integrase interactor 1, also called BAF47 or SNF5). Loss of INI1 expression is nearly ubiquitous among rhabdoid tumors, which is useful to confirm the diagnosis as rhabdoid tumors can be histologically heterogeneous. Heterogeneity in the histologic spectrum of MRTs as well as inflammation in the biopsy led to the difficulty with the initial diagnosis in our case. The histopathology of the biopsy specimen did not exhibit typical features of MRT (Figure 3A), instead showing fibrotic tissue with dense cellular proliferation arranged in a fascicular pattern. Mitotic figures were rare. There was lymphocytic infiltration with scattered plasma cells, eosinophils, and neutrophils, in keeping with the inflammatory infiltrate that can be seen in IMT. Immunostaining was consistent with, albeit nonspecific for, ALK-negative IMT. By contrast, final tumor pathology showed marked nuclear pleomorphism, prominent nucleoli, necrosis with overlying dystrophic calcification, and a high mitotic rate, prompting staining for INI1. Loss of INI1 established the diagnosis of MRT (Figure 3B-C). In the resection specimen, it was clear the inflammatory infiltrate was confined to the superficial portion of the tumor and represented a reactive process.
Concerns surrounding misdiagnosis are complex and include patient harm, ethical disclosure, medicolegal risk, and systemic burdens of medical error(13,14). Our approach was to first to assess and mitigate harm to the patient, and secondly to support the family. In this case, it is unclear whether a delay in diagnosis was clinically harmful. Had the initial biopsy revealed MRT, the patient would have undergone radical cystectomy and cutaneous diversion. The positive tumor margin was posterior, not at the bladder edge, thus radical cystectomy likely would not have averted this margin and subsequent radiation therapy. In the unfortunate event of relapse, we cannot conclude that radical cystectomy would have been preventive given the globally poor disease prognosis. Regarding the physician-family relationship, our approach is to provide support through knowledge, availability, and a clear plan. While we cannot promise a good outcome, we can promise to disclose all information (and be honest when the answer is “I don’t know,”) to assure families they are never alone (we choose to share the attending physician’s cell phone number with our cancer patients), and to always have a next step in place. In our experience, this approach aligns the physician and the family under stressful circumstances which could otherwise lead to a contentious and counterproductive partnership. Moreover, as physicians we support each other, recognizing that there is intrinsic imperfection in all that we do. We share our experience to contribute to the scarce literature on pure MRT of the bladder, and to pass on lessons learned from the initial difficulty with diagnosis. Non-diagnostic bladder biopsy in the setting of bladder MRT has been reported, but unlike in this case, was secondary to inadequate tissue sampling(15). We recommend intraoperative communication with pathology to confirm that adequate tissue has been obtained even when not requesting frozen section for preliminary diagnosis. Furthermore, we advocate for operative lymph node sampling for all solid tumors given the minimal morbidity and potential prognostic and oncologic
benefit. Lastly, our practice has changed to include INI1 immunostaining for all ambiguous soft tissue malignancies.
Conclusion: Extrarenal, extracranial MRT is a rare entity with a poor prognosis. Its rarity and heterogeneity can complicate the diagnosis. Loss of INI1 expression is nearly ubiquitous, and INI1 staining should be considered in all solid tumors when histopathologic diagnosis is ambiguous. Alignment with the family and mutual support among healthcare team members has been central to our approach to all patients who receive bad news.
1. Venkatramani R, Shoureshi P, Malvar J, Zhou S, Mascarenhas L. High dose alkylator therapy for extracranial malignant rhabdoid tumors in children: Malignant Rhabdoid Tumor. Pediatr Blood Cancer. 2014 Aug;61(8):1357–61. 2. Beckwith JB, Palmer NF. Histopathology and prognosis of Wilms tumors: results from the First National Wilms’ Tumor Study. Cancer. 1978 May;41(5):1937–48. 3. Haas JE, Palmer NF, Weinberg AG, Beckwith JB. Ultrastructure of malignant rhabdoid tumor of the kidney: A distinctive renal tumor of children. Hum Pathol. 1981 Jul 1;12(7):646–57. 4. Morgenstern DA, Gibson S, Brown T, Sebire NJ, Anderson J. Clinical and pathological features of paediatric malignant rhabdoid tumours. Pediatr Blood Cancer. 2010 Jan;54(1):29–34. 5. Tomlinson GE, Breslow NE, Dome J, Guthrie KA, Norkool P, Li S, et al. Rhabdoid tumor of the kidney in the National Wilms’ Tumor Study: age at diagnosis as a prognostic factor. J Clin Oncol Off J Am Soc Clin Oncol. 2005 Oct 20;23(30):7641–5. 6. Reinhard H, Reinert J, Beier R, Furtwängler R, Alkasser M, Rutkowski S, et al. Rhabdoid tumors in children: prognostic factors in 70 patients diagnosed in Germany. Oncol Rep. 2008 Mar;19(3):819–23. 7. Islam M, Saltzman AF, Amini A, Carrasco A, Cost NG. Factors Influencing Overall Survival of Children, Adolescents, and Young Adults With High-risk Renal Tumors. Urology. 2018 Oct 1;120:222–30. 8. Oda Y, Tsuneyoshi M. Extrarenal rhabdoid tumors of soft tissue: clinicopathological and molecular genetic review and distinction from other soft-tissue sarcomas with rhabdoid features. Pathol Int. 2006 Jun;56(6):287–95. 9. Duvdevani M, Nass D, Neumann Y, Leibovitch I, Ramon J, Mor Y. Pure rhabdoid tumor of the bladder. J Urol. 2001 Dec;166(6):2337. 10. Chang JH, Dikranian AH, Johnston WH, Storch SK, Hurwitz RS. Malignant extrarenal rhabdoid tumor of the bladder: 9-year survival after chemotherapy and partial cystectomy. J Urol. 2004 Feb;171(2 Pt 1):820–1. 11. Warren KS, Oxley J, Koupparis A. Pure malignant rhabdoid tumour of the bladder. Can Urol Assoc J. 2014;8(3–4):E260–2. 12. Hoare D, Kiddoo D, Stryker T. An Antenatally Detected Pure Malignant Rhabdoid Tumor of the Bladder. Urology. 2019 Jan 1;123:221–3. 13. Wu AW, Cavanaugh TA, McPhee SJ, Lo B, Micco GP. To tell the truth: Ethical and practical issues in disclosing medical mistakes to patients. J Gen Intern Med. 1997 Dec;12(12):770–5. 14. Weingart SN, McL Wilson R, Gibberd RW, Harrison B. Epidemiology of medical error. West J Med. 2000 Jun;172(6):390–3. 15. Savage N, Linn D, McDonough C, Donohoe JM, Franco A, Reuter V, et al. Molecularly confirmed primary malignant rhabdoid tumor of the urinary bladder: implications of accurate diagnosis. Ann Diagn Pathol. 2012 Dec;16(6):504–7.
Figure 1: (A) Bladder ultrasound demonstrating an intravesical mass. (B) The mass and overlying calcifications are re-demonstrated on staging CT scan.
Figure 2: Gross images of the specimen. (A) Intact, endophytic tumor with overlying calcifications. The tumor measured 7.0 x 5.8 x 5.0cm. Note the thickened bladder wall (white arrow). (B) Bisected tumor.
Figure 3: (A) Slide from the initial transurethral biopsy, initially read as most consistent with inflammatory myofibroblastic tumor. (B) Slide from the final tumor resection shows typical findings of rhabdoid tumor including vesicular and eccentric nuclei, prominent nucleoli, and a high mitotic rate. (C) INI1 immunohistochemistry stain shows diffuse loss of INI1 expression in tumor nuclei, with appropriate staining of intra-tumoral endothelial cells serving as the internal control