Case of cerebral toxoplasmosis masquerading as high-grade glioma

Abstract A 72-year-old female status post renal transplant presenting with right hemiparesis, expressive aphasia, and weight loss was found to have a left frontal ring-enhancing lesion with associated vasogenic edema. Imaging was most concerning for high-grade glioma, gliomatosis cerebri with anaplastic transformation, vs solitary metastasis and less concerning for evolving intraparenchymal hemorrhage, abscess, tuberculoma, or fungal granuloma. Maximal safe resection was not feasible. Awaiting stereotactic biopsy results, plans for palliative chemoradiotherapy for presumed glioblastoma were initiated. Frozen pathology review suggested high-grade glioma but ultimate diagnosis of cerebral toxoplasmosis was made. Patient started sulfadiazine, pyrimethamine, and leucovorin. This case identifies an uncommon presentation of cerebral toxoplasmosis whose definitive pathological diagnosis was indispensable to preservation of life. It serves as a critical example of the importance of maintaining a wide differential, as a patient with presumed aggressive terminal cancer was diagnosed with a treatable parasitic infection. We share perspectives from neurosurgery, medical-oncology, radiation-oncology, and infectious disease specialists regarding diagnosis and management. We highlight atypical presentations of cerebral toxoplasmosis, emphasize differential diagnoses, and promote obtaining tissue diagnosis in guiding medical decision making of ring enhancing lesions.