title: Urachal inflammatory myofibroblastic tumor with ALK gene rearrangement: a study of urachal remnants.
abstract: OBJECTIVE
  Abnormalities of the urachus are rare among children and include a patent tract and cyst formation. These structures can also be affected by infection and abscess development. They are usually diagnosed during infancy and treated by surgical resection. Involvement of this remnant by either benign or malignant tumors is very infrequent. A few cases of mesenchymal tumors, such as desmoid tumor and leiomyoma, involving the urachus have been described in published reports.
  
  
  METHODS
  We studied an inflammatory myofibroblastic tumor arising from the urachus in a 10-year-old boy. In addition, we reviewed 101 cases of urachal remnants retrieved from the surgical pathology and autopsy files in the Department of Pathology at the Children's Hospital Boston diagnosed in the past 82 years.
  
  
  RESULTS
  The urachal inflammatory myofibroblastic tumor showed anaplastic lymphoma kinase (ALK) rearrangement by immunohistochemistry and fluorescence in situ hybridization techniques. No other neoplasms were diagnosed in the analyzed population.
  
  
  CONCLUSIONS
  We describe an example of inflammatory myofibroblastic tumor involving the urachus. Involvement of the urachus by tumors is rare, but these should be considered in the differential diagnosis of urachal lesions.
authors.affiliation: Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Alessandra F
authors.initials: AF
authors.lastname: Nascimento
authors.forename: Paola
authors.initials: P
authors.lastname: Dal Cin
authors.forename: Bartley G
authors.initials: BG
authors.lastname: Cilento
authors.forename: Antonio R
authors.initials: AR
authors.lastname: Perez-Atayde
authors.forename: Harry P W
authors.initials: HP
authors.lastname: Kozakewich
authors.forename: Vânia
authors.initials: V
authors.lastname: Nosé
mesh_terms: D000077548:Anaplastic Lymphoma Kinase; D002648:Child; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D006801:Humans; D007124:Immunoenzyme Techniques; D017404:In Situ Hybridization, Fluorescence; D007249:Inflammation; D008297:Male; D047708:Myofibroma / Q000737:chemistry / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D009363:Neoplasm Proteins / Q000032:analysis / Q000235:genetics*; D011505:Protein-Tyrosine Kinases / Q000032:analysis / Q000235:genetics*; D020794:Receptor Protein-Tyrosine Kinases; D012983:Soft Tissue Neoplasms / Q000737:chemistry / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D014496:Urachal Cyst / Q000175:diagnosis; D014497:Urachus / Q000473:pathology*
chemical_list: D009363:Neoplasm Proteins; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases