Abstract

Rosai-Dorfman disease (RDD) is a rare, benign histiocytic disorder of unclear etiology, most commonly presenting with lymphadenopathy - particularly in the cervical region - alongside systemic symptoms such as fever and elevated inflammatory markers. While nodal involvement is typical, extranodal manifestations can occur, and neurological involvement - though uncommon - may present as cerebral pachymeningitis or spinal cord abnormalities. 18F-FDG PET/CT has emerged as a valuable tool for early disease assessment and monitoring. We report the case of a 32-year-old patient with RDD presenting predominantly with meningeal involvement. The patient underwent surgical intervention, followed by treatment with corticosteroids and valproic acid (Depakine). Disease prognosis is closely linked to the extent of involvement. In this case, 18F-FDG PET/CT played a critical role in both treatment planning and response monitoring, demonstrating clear advantages over conventional computed tomography (CT) and Magnetic Resonance Imaging in evaluating disease activity.

Key words: Rosai-Dorfman disease, meningeal involvement, 18F-FDG PET/CT, extranodal histiocytosis.