ROLE OF CYTOLOGY IN THE INTRAOPERATIVE DIAGNOSIS OF CENTRAL DEMYELINATING DISEASE

OBJECTIVE: To determine the usefulness of cytology in the intraoperati ve diagnosis of central demyelinating disorders. STUDY DESIGN: Smears of three multiple sclerosis (MS) plaques and two progressive multifoca l leukoencephalopathy (PML) lesions prepared intraoperatively were exa mined and compared. The cytologic features were contrasted with those of infiltrating astrocytomas. RESULTS: The preparations of demyelinati ng lesions revealed normal or reactive astrocytes and large numbers of foamy macrophages, the key diagnostic finding. The preparations of th e lesions of PML contained virally infected oligodendrocytes. The spec ific cell types were identified easily because cytoplasmic margins cou ld be distinguished. CONCLUSION Cytologic preparations of lesions of P ML and MS permitted rapid identification of the diagnostic features an d distinguished them from infiltrating astrocytomas, the most importan t lesion in the differential diagnosis. The findings demonstrated the utility of cytology in the diagnosis of central demyelinating diseases .