Interesting Images18F-FDG PET/CT Findings in a Patient With Isolated Intracranial Rosai-Dorfman DiseaseDeshayes, Emmanuel, MD*; Le Berre, Jean-Philippe, MD†; Jouanneau, Emmanuel, MD, PhD‡; Vasiljevic, Alexandre, MD§; Raverot, Gérald, MD, PhD¶; Seve, Pascal, MD, PhD∥**Author Information From the *Department of Nuclear Medicine, Hôpital Edouard Herriot, Lyon; †Department of Endocrinology, Hopital d’Instruction des Armées Desgenettes, Lyon; ‡Department of Neurosurgery, Hôpital Neurologique Pierre Wertheimer and §Service de Pathologie et Neuropathologie, Centre de Biologie et Pathologie EST, Groupement Hospitalier EST, ¶Fédération d’Endocrinologie du Pôle Est, and ∥Department of Internal Medicine, Croix-Rousse Hospital, Hospices Civils de Lyon, Lyon; and **University Claude Bernard Lyon 1, Villeurbanne, France. Received for publication November 3, 2011; and revision accepted March 13, 2012. Conflicts of interest and sources of funding: none declared. Reprints: Pascal Sève, MD, PhD, Department of Internal Medicine, Hôpital de la Croix Rousse, 103 Grande Rue de la Croix Rousse, 69317 Lyon Cedex 04. France. E-mail: firstname.lastname@example.org. Clinical Nuclear Medicine: January 2013 - Volume 38 - Issue 1 - p e50-e52 doi: 10.1097/RLU.0b013e31825ae73b Buy Metrics Abstract Rosai-Dorman disease (RDD) or sinus histiocytosis with massive lymphadenopathy is a rare histiocytic disorder first described in 1969. RDD involving the central nervous system is considered to be rare, with fewer than 120 cases reported in the literature. We present a 51-year-old woman with a history of panhypopituitarism, episodic memory disturbance, and a hypothalamic tumor. Stereotaxic hypothalamic lesion biopsy showed histiocytic proliferation positive for S100 protein and CD68+, but negative for CD1a, typical for RDD. 18F-FDG PET/CT 4 months later demonstrated increased hypothalamic metabolic activity. © 2013 Lippincott Williams & Wilkins, Inc.