Isolated cerebral Rosai-Dorfman disease presenting as a sole mass protruding into the fourth ventricle: A case report

Abstract

Rosai-Dorfman disease is a non-Langherans cell histiocytosis typically revealed by a lymphadenopathy. Central nervous system involvement is rare, exceptionally isolated, and usually consists of dural masses mimicking meningioma. Very few reports have described non-dural-based lesions, especially with an intra-ventricular development. We report hereby the case of a Rosai-Dorfman disease in a 30-year-old man presenting as an isolated mass arising from the right cerebellar peduncle and protruding into the fourth ventricle. We provide the results of the MRI examination with a special focus on advanced MRI features. As the diagnosis relies on pathological examination, we also detail the results of the analysis that followed the surgical resection of the mass including the immunohistochemical profile. This report highlights the necessity to consider Rosai-Dorfman disease as a potential diagnosis in case of an infra-tentorial mass and/or intra-ventricular mass.

Keywords: Case Report; Cerebral Ventricles; Magnetic Resonance Imaging; Posterior fossa; Rosai–Dorfman Disease.

Fig. 1

Computerized tomography Axial images: before (A) and after (B) contrast agent administration. Coronal images: before (C) and after (D) contrast agent administration.

Fig. 2

Conventional MRI examination Axial MRI examination showing the lesion protruding into the fourth ventricle. The lesion is iso-intense to grey matter on T1-weighted image (A), hyperintense with a slight adjacent edema on T2-weighted image (B) and homogeneously enhanced on T1-weighted image following administration of gadolinium (C) Apparent diffusion coefficient map (D) shows no abnormality.

Fig. 3

Advanced MRI examination.(A): axial fusion image consisting of cerebral blood volume cartography (rainbow scale) superimposed on enhanced-T1 weighted image (greyscale) showing no lesional hyperperfusion.(B): perfusion curve showing an overshooting of the baseline evocative of blood-brain barrier disruption (C): short echo time MR spectroscopy showing decreased NAA-peak, no alanine peak and a slight lipidic peak.

Fig. 4

Pathological examination.Infiltration of the cerebral tissue by large eosinophilic or foamy macrophages; presence of an emperipolesis (arrow); Hemalum Phloxine - Inset: detail of emperipolesis (phagocytosis of a lymphocyte); Periodic Acid Schiff stain. Original magnification × 400.

Fig. 5

Immunohistochemistry.S100 protein expression by the macrophages. Original magnification × 400.