An unusual presentation of adult cerebral toxoplasmosis

Abstract

<i>Toxoplasma gondii</i> is an opportunistic protozoan. Toxoplasma infection is a rare complication in immunocompromised patients, and reactivation of latent disease is postulated as the main pathogenetic mechanism. We report a patient with chronic myeloid leukaemia who had received a bone marrow transplant, and presented with deteriorating neurological symptoms and multiple contrast-enhancing lesions in the brain and cerebellum. The clinical and imaging differential diagnosis was wide and favoured progressive multifocal leukoencephalopathy (PML) over demyelination, other infections and neoplastic disease. Stereotactic biopsies revealed extensive tissue necrosis with some inflammatory cells, but there was no definite diagnosis. The patient was subsequently diagnosed, at autopsy, with widespread toxoplasmosis of the brain, brain-stem and spinal cord; wherein the lesions were predominantly in the periventricular regions. We will discuss some of the challenges in diagnosing toxoplasmosis in small biopsies of the brain, and demonstrate the unusual periventricular distribution of the lesions in this case. This case emphasises the importance of maintaining a high level of clinical suspicion for this rare and often fatal infection, as serology is often unhelpful in immunocompromised patients and the imaging findings may not be classical.