Rosai-Dorfman Disease: Imaging and Updates.

Abstract

Rosai-Dorfman disease (RDD) is a rare, clinically heterogeneous, multisystem, non-Langerhans cell histiocytosis. The discovery of recurrent and somatic mutations in the MAPK signaling pathway in a subset of these patients, starting in 2016, subsequently led to a reclassification of RDD from an inflammatory disorder to a neoplastic process. It is now included in the revised 2022 World Health Organization classification of hematolymphoid tumors. The hallmark of RDD is massive painless cervical lymphadenopathy, although any nodal station can be affected. RDD can also manifest as histiocyte-rich soft-tissue infiltrates in any organ system. Multiple varied pathologic conditions, including autoimmune and hereditary disorders and even malignancies, can coexist with RDD and thus further confound the clinical findings. Radiologic findings often provide the first clue to the presence of RDD by detecting nonspecific lymphadenopathy or masslike extranodal disease. However, imaging findings are nonspecific, similar to the clinical manifestations, and are best interpreted in conjunction with histologic features. Imaging allows determination of target sites for biopsy and the extent of the disease, helps predict prognosis, and assesses treatment response. The rarity of the disease and a lack of uniform guidelines make management challenging. Nevertheless, radiologic findings help assess treatment response and guide further management. The authors discuss various radiologic findings of RDD, along with differential diagnoses, by using an organ system-based approach and briefly describe the consensus management guidelines for RDD discussed in the 2016 annual meeting of the 32nd Histiocyte Society. ^©RSNA, 2026 Supplemental material is available for this article.