In the cases where it is not possible to explain the occurrence of a rapid and progressive cognitive decline through usual non-invasive examinations, the use of cerebral biopsy has been proposed. In a trial performed by Emory University in Atlanta, some neurosurgeons have re-examined the medical records of 51 adults undergoing cerebral biopsy between 1999 and 2008 to determine the causes of an acute or sub-acute cognitive decline. Subjects with mass cerebral lesions, with malignant tumours or HIV infection have been excluded. The commonest pre-operative diagnoses have been: vasculitis (24 cases), encephalitis (8 cases), Creutzfeld-Jakob’s disease (7 cases). Cerebral biopsy has established diagnosis in 18 cases: Creutzfeld-Jakob’s disease (8), amyloidosis (3), lymphoma (2), encephalitis (2), demyelination (2) and infarction (1). The other biopsies have only identified a non-specific inflammation (20) or they have resulted completely normal (13). Biopsy results have implied a new therapeutical approach only in 4 cases and, only in 2 cases, subjects with lymphoma have shown a benefit from the new treatment. In two subjects, there have been post-biopsy cerebral bleedings.
It is true that cerebral biopsy has established a sure diagnosis in about 1/3 of cases, but it is also true that only 2 patients have had a benefit from that procedure, apart from the risks linked to the procedure. Cerebral biopsy remains a procedure to be used only in particular cases and with all possible precautions: it cannot certainly become a routine procedure. A little note: vasculitis, diagnosed in about half of the patients, has been confirmed in no cases by biopsy: a mistaken diagnosis? An overestimation of a little frequent disease?
