title: Rosai-Dorfman disease involving gallbladder and liver-Report of a case.
abstract: BACKGROUND
  Rosai-Dorfman disease (RDD), also known as sinus histiocytosis with massive lymphadenopathy, is a rare histiocytic disorder of unclear etiology. Lymphadenopathy commonly affects the lymph nodes of the neck and the head, but extranodal involvement has been observed too.
  
  
  METHODS
  We describe an unusual case of RDD with involvement of the gallbladder, liver and cystic lymph node, clinically manifested as an exacerbated cholecystitis. The patient underwent a cholecystectomy with atypical liver resection because the finding was macroscopically suspected of gallbladder cancer. The diagnosis of RDD was confirmed by immunohistochemical study.
  
  
  CONCLUSIONS
  Histological features of RDD include histiocytic proliferation, emperipolesis and positive immunostaining for S-100 protein and typically negative for CD1a. Gastrointestinal localization of RDD, especially in the liver and pancreas, is extremely rare. Typically, the liver is affected as a part of systematic spread of RDD. We have not found reports for involvement of the gallbladder.
  
  
  CONCLUSIONS
  The presented case is valuable due to its rarity and difficulty in differential diagnosis.
authors.affiliation: Department of General and Hepato-Pancreatic Surgery, University Hospital "Alexandrovska" - Sofia, Medical University - Sofia, 1 G.Sofiiski Str., 1431 Sofia, Bulgaria. Electronic address: elena_arabadjieva@abv.bg.
authors.forename: Elena
authors.initials: E
authors.lastname: Arabadzhieva
authors.affiliation: Department of General and Hepato-Pancreatic Surgery, University Hospital "Alexandrovska" - Sofia, Medical University - Sofia, 1 G.Sofiiski Str., 1431 Sofia, Bulgaria.
authors.forename: Atanas
authors.initials: A
authors.lastname: Yonkov
authors.affiliation: Department of General and Hepato-Pancreatic Surgery, University Hospital "Alexandrovska" - Sofia, Medical University - Sofia, 1 G.Sofiiski Str., 1431 Sofia, Bulgaria.
authors.forename: Sasho
authors.initials: S
authors.lastname: Bonev
authors.affiliation: Department of General and Hepato-Pancreatic Surgery, University Hospital "Alexandrovska" - Sofia, Medical University - Sofia, 1 G.Sofiiski Str., 1431 Sofia, Bulgaria.
authors.forename: Dimitar
authors.initials: D
authors.lastname: Bulanov
authors.affiliation: Department of General and Hepato-Pancreatic Surgery, University Hospital "Alexandrovska" - Sofia, Medical University - Sofia, 1 G.Sofiiski Str., 1431 Sofia, Bulgaria.
authors.forename: Ivanka
authors.initials: I
authors.lastname: Taneva
authors.affiliation: Department of General and Clinical Pathology, Medical University - Sofia, 2 Zdrave Str., 1431 Sofia, Bulgaria.
authors.forename: Tatyana
authors.initials: T
authors.lastname: Pirdopska
authors.affiliation: Department of General and Clinical Pathology, Medical University - Sofia, 8 Bialo more Str., 1527 Sofia, Bulgaria.
authors.forename: Ivan
authors.initials: I
authors.lastname: Terziev
authors.affiliation: Department of General and Hepato-Pancreatic Surgery, University Hospital "Alexandrovska" - Sofia, Medical University - Sofia, 1 G.Sofiiski Str., 1431 Sofia, Bulgaria.
authors.forename: Violeta
authors.initials: V
authors.lastname: Dimitrova
keywords: Extranodal disease; Gallbladder; Liver; Rosai–Dorfman disease; Sinus histiocytosis