Gliomatosis cerebri: cytologic and autopsy findings in a case involving the entire neuraxis

We describe the case of a 7-year-old girl who was clinically diagnosed as h aving a pontine glioma based on magnetic resonance imaging studies. Neoplas tic cells were identified upon cytologic examination of cerebrospinal fluid . Autopsy studies revealed an anaplastic astrocytoma (WHO grade III) diffus ely infiltrating the cerebral hemispheres, brain stem, cerebellum, leptomen inges, and spinal cord to the level of the conus medullaris. The Ki-67 labe ling index focally approached 30%. Although many of the neoplastic cells di splayed elongated twisted nuclei reminiscent of microglia, these cells stai ned intensely for glial fibrillary acidic protein, supporting an astrocytic origin. Unusual features of this case of gliomatosis cerebri include invol vement of the entire central neuraxis, correlation with pre-mortem lumbar p uncture cytology, and a markedly elevated Ki-67 labeling index.