Rosai–Dorfman disease involving gallbladder and liver—Report of a case.

Introduction 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. Presentation of case 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. Discussion 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. Conclusion The presented case is valuable due to its rarity and difficulty in differential diagnosis. [ABSTRACT FROM AUTHOR]