FDG PET/CT in the Evaluation of a Rare Case of Multisystem Involvement in Newly Diagnosed Rosai–Dorfman–Destombes Disease

Rosai–Dorfman–Destombes disease (RDD) is a rare histocytic disorder with a broad spectrum of clinical presentations. The disease typically presents with lymphadenopathy but may involve multiple systems. Usually, RDD lesions demonstrate intense (18)F-Fluorodeoxyglucose (FDG) uptake in positron emission tomography/computed tomography (PET/CT) imaging due to the inflammation and infiltration with high metabolic process of the disease. Here, we describe a rare case of 37-year-old man who presented with multiple systemic symptoms, including fever, weight loss and bilateral cervical, and inguinal lymphadenopathy who underwent FDG PET/CT for detection of disease extension. This case highlights the role of FDG PET/CT in establishing the disease extent in newly diagnosed RDD and guiding the therapeutic recommendations and for follow-up to monitor the disease response to therapy. To the best of our knowledge, this is the first case report from Saudi Arabia highlighting the role of FDG PET/CT in newly diagnosed RDD.