Neurotoxoplasmosis in Immunocompetent Patients Mimicking Lymphoproliferative Disease (P5.9-036)

Objective: We present a case of immunocompetent neurotoxoplasmosis mimicking lymphoproliferative disease in the neuroimaging. Background: Neurotoxoplasmosis is a disease often associated with immunocompromised patients, being rare in immunocompetent patients. The common presenting symptom of cerebral toxoplasmosis is headache, often accompanied by fever and altered mental status. The common neurological signs include motor weakness and speech disturbances. Design/Methods: Not applicable Results: A 60-year-old man was admitted with 2 days history of headache and right-sided weakness without altered state of consciousness. Neurologic examination included right hemiparesis. CSF showed 15 cells/mm3 (predominantly lymphomononuclear), flow cytometry immunophenotypic analysis in the CSF was normal. Viral serologies, tumor markers, protein electrophoresis were normal. MRI showed hyperintense T2/FLAIR sequences compromising the left frontal and parietal lobes, leptomeningeal compartment, with heterogeneous enhancement after contrast administration. Spectroscopy showed an elevated lipid lactate peak. Perfusion demonstrated increased microvascular permeability. Toxoplasmosis serology was negative. T-lymphocyte count and serum immunoglobulin levels, as well as complement was normal, performed to exclude immunodeficiency. Initially, a diagnosis of neoplastic lymphoproliferative was suspected in view of the patient’s age, history, and imaging features, although it may not rule out inflammatory/infectious diseases. The patient was submitted to stereotactic brain biopsy, revealing necrotic brain parenchyma with predominately acute inflammation, with encephalitis pattern and immunohistochemical showing Toxoplasma gondii in the brain parenchyma. The treatment consisted in sulfadiazine and pyrimethamine for six weeks. His neurological features improved completely as well as MRI findings, showing regression of the lesions with no pathological contrast enhancement. Conclusions: In immunocompetent individuals, the probability of neurotoxoplasmosis is very low. In consequence, presumptive diagnosis could not be considered in a patient with a focal cerebral lesion. We present a case of neurotoxoplasmosis in an immunocompetent patient without suggestive findings in neuroimaging, with diffuse encephalitis and demonstrating a pattern that mimics lymphoproliferative disorders. Disclosure: Dr. Ferreira Lima has nothing to disclose. Dr. Guimaraes de Queiroz has nothing to disclose. Dr. Teixeira has nothing to disclose. Dr. Mantelatto Bonsi has nothing to disclose. Dr. Yonekura Inada has nothing to disclose. Dr. Escorcio-Bezerra has nothing to disclose. Dr. Penteado Lancellotti has nothing to disclose. Dr. Baeta has nothing to disclose.