P11.10 * CEREBRAL TOXOPLASMOSIS IN A DIFFUSE LARGE B CELL LYMPHOMA PATIENT

Abstract

INTRODUCTION: Toxoplasmosis is an opportunistic protozoal infection that has until now possibly been an underestimated cause of encephalitis in patients with hematological malignancies, independent of stem cell or bone marrow transplant. T and B cell depleting regimens are probably an important risk factor for reactivation of a latent toxoplasma infection in seropositive patients with hematological malignancies. CASE REPORT: We present a 62 year-old HIV negative right-handed Caucasian female with diffuse large B cell lymphoma that presented with sudden onset of high fever, pancytopenia, headache, altered mental status and ataxia a few days after receiving her final, 8th cycle of R-CHOP (rituximab, cyclophosphamide, vincristine, doxorubicin, prednisolone) chemotherapy regimen. On the basis of CT imaging, which revealed diffuse hypodensities spreading from the right cerebral hemisphere across corpus callosum into the left cerebral hemisphere, with additional hypodensities involving the cerebellum, a progression of lymphoma to the central nerve system (CNS) was suspected. However, MRI of the head revealed multiple T2 and FLAIR hyperintense parenchymal lesions with mild surrounding edema, located in both cerebral and cerebellar hemispheres, that were hypointense on T1 sequences and demonstrated moderate rim enhancement after contrast administration. The CSF PCR was positive for Toxoplasma gondii and serological analysis revealed borderline positive IgG and negative IgM antibodies. The patient was diagnosed with toxoplasmic encephalitis and succesfully treated with sulfadiazine, pyrimethamine and folic acid. At follow-up, neurological deficits were almost completely reversed and MRI showed partial resolution of cerebral lesions and reduction of edema. Due to the need for maintenance therapy with rituximab for lymphoma remission, the patient now continues with secondary prophylaxis of toxoplasmosis. CONCLUSION: With this case report we wish to emphasize the need to consider cerebral toxoplasmosis in patients with hematological malignancies on immunosuppresive therapy when presenting with new cognitive or neurologic deficits. In such patients, numerous differential diagnoses for cerebral toxoplasmosis exist, among which CNS lymphoma is the most difficult to distinguish from. Left untreated, cerebral toxoplasmosis has a high mortality rate, therefore early recognition and treatment is of essential importance.