CORRELATION OF MRI AND CSF CYTOLOGY IN THE DIAGNOSIS OF MEDULLOBLASTOMA SPINAL METASTASES

Background. Medulloblastoma frequently spreads to involve the spinal c ord, which significantly reduces patient survival and determines wheth er chemotherapy is utilised and the dose of irradiation to the neuraxi s. Staging is usually achieved by MRI of the spine and/or cytology of CSF, both methods having their limitations. Objective. To determine wh ether there is a correlation between CSF cytology and the demonstratio n of spinal metastases by MRI and whether CSF cytology is useful when spinal MRI is equivocal. Materials and methods. All cases of medullobl astoma diagnosed at our hospital between 1992 and 1997 were identified . Of 26 cases, 11 presentations (age range 4 months to 12 years) had b oth CSF cytology (either from the cisterna magna or lumbar puncture) a nd spinal MRI. The MR studies were reviewed for the presence of metast ases and the CSF cytology for the presence of tumour cells. Results. W e found 100% correlation between MRI and CSF cytology for samples take n by lumbar puncture (four negative and three positive on both investi gations). No correlation was demonstrated when CSF samples were taken from the cisterna magna. Conclusions. Our data suggest that lumbar CSF cytology may be useful when the MRI is equivocal for the presence of metastatic involvement of the spine by medulloblastoma.