Vanishing glioblastoma after corticosteroid therapy: Does this occurrence modify our surgical strategy?

Glioblastoma multiforme is a malignant adult intracranial tumor; it accounts for 10–15% of all intracranial tumors, with a reported male preponderance of 6:4. The location of glioblas-toma in the brain is principally supratentorial. Brain metastases, abscesses, primary central nervous system lymphoma (PCNSL) and primary CNS lymphomas should be considered in the differential diagnosis of this lesion. Glioblastomas are not known to change their radiological appearance and contrast enhancement pattern under steroid therapy. On the contrary, PCNSL typically exhibits this behavior. MRI is the most sensitive radiological procedure for detecting brain lymphoma, but its features are often not diag-nostic, rendering stereotactic biopsy necessary for deciding final surgical strategy. Biopsy is more likely to yield diagnostic tissue if it is performed prior to the administration of corticosteroids, which by killing the malignant tumor cells, may obscure the diagnosis. Furthermore, the spectral patterns seen in PCNSL may be simi-lar to glioblastoma multiforme. Proton magnetic spectroscopy in PCNSL characteristically includes a loss of N-acetylaspartate (NAA), a decrease in creatine (Cr), and a dramatic increase in choline (Cho) and lactate (Lac). The most specific finding for PCNSL on MRS is an increase in lipid resonance. The authors describe a case of a right periventricular glioblastoma multiforme in an adult patient, with partial involvement of the splenium of the corpus callosum, whose radiological appearance dramatically changed following corticosteroid therapy. This occurrence led us to change our surgical planned strategy, causing a considerable delay in definitive tumor removal and administration of adjuvant therapy. The case is discussed in the light of the pertinent literature.