[A case of multifocal glioblastoma with ring enhancement, mimicking cerebral toxoplasmosis with ring-enhanced lesions].

A 57-year-old male patient with a history of daily contact with stray cats was transferred to our hospital with weakness in the left limb and mild disturbance of consciousness. At presentation, he had no fever or signs of meningeal irritation. Cerebrospinal fluid examination revealed lymphocytic pleocytosis; however, the cerebrospinal culture was negative. Computed tomography of the thorax and abdomen showed no abnormalities. Gadolinium-enhanced brain MRI revealed multiple contrast-enhanced lesions in the periventricular white matter and enhanced lateral ventricles. Under the suspicion of cerebral toxoplasmosis, trimethoprim-sulfamethoxazole was administered, but his symptoms gradually worsened. Histopathological findings of the first brain biopsy did not reach the definitive diagnosis. The tissue culture detected Propionibacterium acnes. Despite changes in antibiotics (ceftriaxone and ampicillin), his symptoms progressed. The second brain biopsy revealed diffuse proliferation of atypical glial cells with irregular size of nuclei and necrosis. The diagnosis was glioblastoma, IDH-wild type, CNS WHO grade 4. The radiological findings in this case were initially recognized as isolated multiple lesions with surrounding vasogenic edema, but we authors should have suspected the brain tumor which spreads through the corpus callosum. Multifocal glioblastomas, a rare type of glioblastoma, has worse prognosis than unifocal glioblastoma. This case also emphasizes the importance of the appropriate timing of brain biopsy and careful validation of biopsy sampling.