Differential diagnosis in Rosai-Dorfman disease: A rare case of isolated hepatic presentation mimicking a metastatic tumor with positive 18-FDG uptake.

Rosai-Dorfman disease (RDD) is also called sinus histiocytosis with massive lymphadenopathy, and it is caused by a histiocytic disorder with unclear etiology. It usually involves cervical lymph nodes, but it may also present with extranodal involvement. We report a rare condition of isolated hepatic RDD without nodal involvement, clinically manifested with three-month abdominal pain and tenderness of the right hypochondrium. CT- and PET-CT scans were compatible with a secondary lesion from an unknown primary tumor. Therefore, the patient underwent an atypical liver resection. Immunohistochemistry and histological results were compatible with a diagnosis of RDD. RDD is characterized by phenomena of emperipolesis, histiocytic proliferation and positive immunostaining for CD14, CD68 and S-100 protein. Cases of isolated gastrointestinal localization of RDD are particularly rare, especially in the liver. Instrumental exams might confuse RDD with other malignancies. RDD is a rare entity, which might be misdiagnosed using PET-CT due to its similarities with malignant tumors. An accurate multidisciplinary approach may help to clear diagnostic clues of this uncommon disease.

Gazia C ，Giordano L ，Diodoro MG ，Compalati I ，Avantifiori R ，Grazi GL ... -  《-》

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

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. 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. 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. The presented case is valuable due to its rarity and difficulty in differential diagnosis.

Arabadzhieva E ，Yonkov A ，Bonev S ，Bulanov D ，Taneva I ，Pirdopska T ，Terziev I ，Dimitrova V ... -  《International Journal of Surgery Case Reports》

Extranodal soft tissue Rosai-Dorfman disease of the head and neck and its diagnostic difficulty.

Rosai-Dorfman disease (RDD) is a rare proliferative histiocytic disorder that is characterized by persistent massive lymphadenopathy mimicking malignant tumors. Extranodal RDD is uncommon, and more severe fibrosis and fewer histiocytes in lesions make the diagnosis of RDD more difficult than that of nodal RDD. We herein described a 31-year-old male patient with isolated soft tissue RDD of the head and neck. The patient was referred to our hospital with a right neck mass. Computed tomography (CT) scans showed a diffuse enhanced tumor with an unclear border in the right side of the neck. 18F-fluorodeoxyglucose positron emission tomography (PET)/CT revealed high uptake in the corresponding lesion. Second wide local excisional biopsy led to a diagnosis of RDD, and immunohistochemistry was useful for diagnosing RDD. A systemic treatment with steroids improved his symptoms, including the neck mass. Physicians need to consider the diagnostic difficulty associated with extranodal soft tissue RDD as well as its rarity.

Yajima M ，Nakajima K ，Hirato J ，Chikamatsu K ... -  《-》

A Case of Rosai-Dorfman Disease Presenting as an Isolated Pleural Plaque.

Rosai-Dorfman disease (RDD) is a rare non-Langerhans histiocytic disorder primarily involving lymph nodes. Extranodal RDD has a heterogenous presentation, and isolated pulmonary involvement is rare. We report the only case of RDD presenting as an isolated pleural mass. Our patient was a 55-year-old female with multiple comorbidities who presented with chest pain. Imaging revealed an enlarging pleural-based lesion. She underwent resection of the pleural mass, showing an atypical histiocytic infiltrate in a prominent background of collagenous fibrosis. Immunohistochemistry shows CD1a-negative and S100-positive atypical histiocytic cells demonstrating emperipolesis, confirming the diagnosis of RDD. She is currently on six-month CT surveillance with no recurrence of the disease. This case highlights the unique pulmonary presentation of RDD. It also underscores that observations may be appropriate in isolated asymptomatic pleural involvement cases.

Rathinam A ，Gupta S ，Khanam R ，Sahai T ... -  《Cureus》

Fourth Ventricular Rosai-Dorfman Disease Mimicking Intraventricular Tumor in Young Adult: A Rare Case Report.

Rosai-Dorfman disease (RDD) or sinus histiocytosis with massive lymphadenopathy can present with or without systemic disease. It is a benign histioproliferative disorder characterized by generalized lymphadenopathy, weakness, anemia, and rarely extranodal involvement. While RDD most commonly affects lymph nodes, extranodal involvement of multiple organs has been reported, including the central nervous system (CNS). However, CNS involvement in RDD is rare and is not well characterized. Isolated involvement of the fourth ventricle is even rarer. Such lesions may be mistaken for intraventricular tumors such as ependymoma or medulloblastoma. This report highlights the necessity to consider RDD as a differential diagnosis in case of intraventricular space-occupying lesion.

Chougule MV ，Prabhakar S ，Tadwalkar N ，Ranade A ... -  《-》