Cerebral toxoplasmosis in a diffuse large B cell lymphoma patient

Abstract

Toxoplasmosis is an opportunistic protozoal infection that has until now probably 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 these patients. 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, headache, altered mental status, ataxia and pancytopenia, a few days after receiving her final, 8^th cycle of R-CHOP chemotherapy regimen. A progression of lymphoma to the central nerve system was suspected. MRI of the head revealed multiple T2 and FLAIR hyperintense parenchymal lesions with mild surrounding edema, located in both cerebral and cerebellar hemispheres, that demonstrated moderate gadolinium enhancement. The CSF PCR was positive for Toxoplasma gondii. The patient was diagnosed with toxoplasmic encephalitis and succesfully treated with sulfadiazine, pyrimethamine and folic acid. Due to the need for maintenance therapy with rituximab for lymphoma remission, the patient now continues with secondary prophylaxis of toxoplasmosis. 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 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 are of essential importance.