In November 2009 a 23-year-old Chinese man presented to the emergency department with a 7-day history of helmet headache radiating to the nuchal region and associated with vomiting, confusion, and fever. Physical examination showed modest neck stiffness, lateral decubitus position, and hyper-excitable tendon reflexes. Babinski and Lasegue signs were negative bilaterally. The patient underwent brain and cervical spine CT scan, which was unremarkable. LP revealed CSF with increased pressure, lymphocytic pleocytosis, decreased glucose, and increased protein levels. Bacterial antigen detection test on CSF was negative, as were CSF bacterial and fungal cultures. CSF acid-fast bacilli smear and culture were negative. Broad-spectrum parenteral therapy with acyclovir, cefotaxime, chloramphenicol, mannitol, and dexamethasone was started. In the following days the patient still complained of insomnia, diplopia, headache, neck stiffness, and pain in the sacral region. Eye and ENT exams were unremarkable. Therefore, a second LP was performed. CSF had the same characteristics as the first LP. The following blood test results were all negative: antibodies against Herpes simplex virus types 1 and 2, HIV, hepatitis A, B, and C viruses, Widal's and Wright's serodiagnosis, VDRL and TPHA, QuantiFERON-TB, Western blot test for Lyme disease, and parasitological stool exam. A brain and spinal cord MRI was performed (Figure 1), revealing widespread arachnoiditis and small septated cysts with CSF-like signal in the cisterna magna, within the fourth ventricle, and at the level of L3-L4. These findings were likely due to arachnoiditic adhesions. Differential diagnosis included toxoplasmosis, fungal abscess, primary or metastatic brain tumour, vasculitis, tuberculoma, and neurocysticercosis. However, the patient had no evidence of immunodeficiency and no predisposing factors for immunocompromise. CSF cultures for Mycobacterium tuberculosis and QuantiFERON-TB were negative. Cysticercus-specific immunoglobin G antibodies were detected by ELISA in the CSF. The patient received albendazole (15 mg/kg/day) and dexamethasone (5 mg/day) for 4 weeks, with progressive resolution of neurological symptoms. A second MRI performed 6 months later confirmed the regression of the lesions.