OBJECTIVE: In general, glioblastomas multiforme (GBM) arise in the supratentorial region, but in less than 4% of cases they also occur in the posterior fossa, particularly in the cerebellum. Furthermore, a minority of malignant gliomas are multifocal. We report on an unusual case with infratentorial multifocal lesions, suspicious for metastases, which turned out to be a multifocal GBM of the posterior fossa. PATIENT AND METHOD: A 69-year-old woman presented with recurring episodes of vertigo, headache, and progressive weight loss. Three multifocal cerebellar and brainstem lesions highly suspicious for metastases were identified by magnetic resonance imaging (MRI). Workup for malignancy elsewhere in the body was negative. RESULTS: The patient underwent craniotomy with successful resection of the tumor in the cerebellar vermis with an excellent outcome and uneventful postsurgical course. Histopathology of the tumor revealed features consistent with the diagnosis of GBM and ruled out metastatic lesions. Workup for molecular genetics characterized this tumor as a primary GBM. The patient initially responded to treatment with radiation therapy and temozolomide but died after 10 months with a tumor relapse. CONCLUSION: We discuss the unusual aspects of multifocal primary GBMs in the posterior fossa. Although rare, they should be considered in the differential diagnosis of cerebellar tumors, which stresses the importance of a surgical treatment to establish a histological diagnosis because there are no reliable radiographic criteria for distinguishing multifocal infratentorial gliomas from multiple metastases and other tumor entities. The differentiation between a primary and secondary cerebellar GBM did not lead to any change of the treatment strategy in this case. Georg Thieme Verlag KG Stuttgart · New York.
OBJECTIVE: In general, glioblastomas multiforme (GBM) arise in the supratentorial region, but in less than 4% of cases they also occur in the posterior fossa, particularly in the cerebellum. Furthermore, a minority of malignant gliomas are multifocal. We report on an unusual case with infratentorial multifocal lesions, suspicious for metastases, which turned out to be a multifocal GBM of the posterior fossa. PATIENT AND METHOD: A 69-year-old woman presented with recurring episodes of vertigo, headache, and progressive weight loss. Three multifocal cerebellar and brainstem lesions highly suspicious for metastases were identified by magnetic resonance imaging (MRI). Workup for malignancy elsewhere in the body was negative. RESULTS: The patient underwent craniotomy with successful resection of the tumor in the cerebellar vermis with an excellent outcome and uneventful postsurgical course. Histopathology of the tumor revealed features consistent with the diagnosis of GBM and ruled out metastatic lesions. Workup for molecular genetics characterized this tumor as a primary GBM. The patient initially responded to treatment with radiation therapy and temozolomide but died after 10 months with a tumor relapse. CONCLUSION: We discuss the unusual aspects of multifocal primary GBMs in the posterior fossa. Although rare, they should be considered in the differential diagnosis of cerebellar tumors, which stresses the importance of a surgical treatment to establish a histological diagnosis because there are no reliable radiographic criteria for distinguishing multifocal infratentorial gliomas from multiple metastases and other tumor entities. The differentiation between a primary and secondary cerebellar GBM did not lead to any change of the treatment strategy in this case. Georg Thieme Verlag KG Stuttgart · New York.