title: Molecularly confirmed primary malignant rhabdoid tumor of the urinary bladder: implications of accurate diagnosis.
abstract: Malignant rhabdoid tumors (MRTs) are well recognized in the kidney and extrarenal sites such as soft tissues, retroperitoneum, and bladder but are classified as atypical teratoid/rhabdoid tumors in the central nervous system. The unifying features of both extracranial MRT and atypical teratoid/rhabdoid tumors are the exon deletions/mutations of the SMARCB1 (SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily b, member 1) gene in 22q11.23 and resulting loss of SMARCB1/INI1 (integrase interactor 1) protein expression by immunohistochemistry. We herein report a case of extrarenal rhabdoid tumor confined to the bladder in a 3-year-old child, diagnosed by histopathology and confirmed by immunohistochemical and molecular studies. This is only the fourth molecularly proven primary MRT of the bladder to be reported. The patient's peripheral blood was negative for the deletions observed in the tumor, thereby confirming a sporadic origin for the tumor. Given the possible dismal outcome, urgency for definitive diagnosis to institute intensive multimodality therapy, histopathologic differential diagnosis with rhabdomyosarcoma and urothelial carcinoma with rhabdoid features, and lack of consensus management guidelines, oncologists, urologists, and pathologists must be aware of this entity. Evaluation for a germ line SMARCB1 alteration may greatly aid risk stratification and family planning.
authors.affiliation: Department of Pathology, Medical College of Georgia, Augusta, GA 30912, USA. NSavage@georgiahealth.edu
authors.forename: Natasha
authors.initials: N
authors.lastname: Savage
authors.forename: Dan
authors.initials: D
authors.lastname: Linn
authors.forename: Colleen
authors.initials: C
authors.lastname: McDonough
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Donohoe
authors.forename: Arie
authors.initials: A
authors.lastname: Franco
authors.forename: Victor
authors.initials: V
authors.lastname: Reuter
authors.forename: Paul W
authors.initials: PW
authors.lastname: Biddinger
authors.forename: Katherine W
authors.initials: KW
authors.lastname: Eaton
authors.forename: Jaclyn A
authors.initials: JA
authors.lastname: Biegel
authors.forename: Suash
authors.initials: S
authors.lastname: Sharma
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D001706:Biopsy; D002675:Child, Preschool; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D003937:Diagnosis, Differential; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D018335:Rhabdoid Tumor / Q000188:drug therapy / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D000071796:SMARCB1 Protein; D014057:Tomography, X-Ray Computed; D014157:Transcription Factors / Q000235:genetics; D014463:Ultrasonography; D001743:Urinary Bladder / Q000000981:diagnostic imaging / Q000473:pathology; D001749:Urinary Bladder Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology* / Q000601:surgery
chemical_list: D014408:Biomarkers, Tumor; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; D014157:Transcription Factors