Neuro-Behçet's disease with atypical subcortical nodular lesions: A case report and treatment approach.

Neuro-Behçet's disease (NB) is a rare complication of Behçet's disease (BD) characterised by central nervous system involvement. While NB typically presents with brainstem lesions, we report an unusual case of NB in a 27-year-old male with multiple subcortical nodular brain lesions but without brainstem, thalamic, or basal ganglia involvement, making this presentation exceptionally rare. The patient had a prior diagnosis of BD and was HLA-B51 positive. He presented with a sudden loss of consciousness, which was attributed to a seizure. Imaging studies showed low-density areas in the white matter of the bilateral temporal lobes and the right frontoparietal lobe on brain CT. Cerebrospinal fluid examination indicated elevated initial pressure and protein concentration, along with increased interleukin-6. Despite presenting with nodular brain lesions, distinguishing between NB and infectious diseases such as tuberculosis (TB) was challenging, and required brain biopsy revealing vasculitis. However, even with this biopsy result, TB could not be ruled out, so TB was treated at the same time. Treatment with anti-TB drugs and standard steroid therapy initially failed to improve the patient's condition. However, increasing the steroid dosage considering the increased steroid degradation by rifampicin, including pulse therapy with 2 g of methylprednisolone, followed by 18 mg of betamethasone, led to remission of the nodular brain lesions and resolution of the nasopharyngeal ulcer. This case highlights the diagnostic challenge of differentiating between NB and TB based on imaging alone and the potential efficacy of high-dose steroid therapy in cases of steroid-resistant NB with subcortical nodular brain lesions.