An intractable case of primary intra-axial central nervous system Rosai-Dorfman disease.

Background: Rosai-Dorfman disease (RDD) is a rare histiocytic disorder with a typically benign clinical course. However, isolated involvement of the central nervous system (CNS), particularly in the form of primary intra-axial disease, is exceedingly rare. We report an intractable case of intra-axial CNS RDD with an atypical clinical presentation. Case Description: A woman in her 60s presented with gradually progressive left hemiplegia. Magnetic resonance imaging demonstrated a solid intra-axial mass (30-mm diameter) in the right frontal lobe, located in the primary motor cortex, with homogeneous gadolinium enhancement and extensive peritumoral edema. Given its eloquent location, an open biopsy was performed, and histopathological examination confirmed the diagnosis of RDD. Treatment with corticosteroids and cladribine resulted in temporary tumor regression, but the lesion subsequently progressed and exhibited an intractable clinical course. The patient developed worsening neurological deficits and additional intracranial lesions, and she ultimately died approximately 30 months after the disease onset. Conclusion: Two cases of death directly caused by intra-axial CNS RDD were previously reported; in both cases, surgical treatment had not been possible. In our case, the tumor was in the primary motor area and challenging to resect. Taken together, total surgical resection may be required to achieve disease control in patients with intra-axial CNS RDD.