May 2000: 35 year old male with a left temporal lobe mass - Diagnosis: Cerebral toxoplasmosis.

The May COM: A 35-year-old, previously healthy male presented with transien t symptoms of mild speech impairment. A CT scan showed a left temporal mass lesion suggestive of glioblastoma. Histological examination of the biopsy revealed a mixed cell infiltrate, while only PCR tests demonstrated the pre sence of toxoplasma gondii DNA in the specimen. Thereafter, HIV serology es tablished the diagnosis of advanced HIV infection, constituting the cerebra l lesion as AIDS-defining disease. Upon anti-toxoplasma therapy, the clinic al course was favorable and follow-up CT scans demonstrated a marked regres sion of the lesion. Under a triple antiretroviral drug regime, the patient is free of symptoms six months after the initial presentation. The value of molecular pathological tools as a supplement to histological examinations on biopsy specimens is stressed.