Presentation
57 male tourist presenting with a four week history of global headache, increasing confusion and expressive and receptive dysphasia.
Patient Data
An irregular heterogenous partially-enhancing mass, with cystic/necrotic components, is located medially in the left temporo-occipital and inferior parietal regions. This appears to be of intra-ventricular/subependymal origin, invading adjacent parenchyma, with extensive surrounding vasogenic edema and mass effect. The left lateral ventricular atrium is severely compressed/replaced and displaced laterally, with obstructive dilatation of the temporal horn. Two vividly enhancing satellite nodules are located posterior to the main tumor mass, with the larger, apparently intra-ventricular occipital nodule demonstrating several prominent feeding vessels and adjacent pathologic ependymal enhancement. In addition, a remote peripherally-enhancing 10 mm diameter nodular tumor focus is interposed between the left cerebral peduncle and posterior cerebral artery.
The patient underwent a left parieto-occipital craniotomy and tumor debulking.
A left parieto-occipital craniotomy has been performed and approximately the lateral two thirds of the left posterior temporal tumor has been resected, leaving a fluid filled cavity. The surgical tract crosses the left occipital white matter and is filled with hematoma intensity material. Post contrast views show continued enhancement of the medial and inferior aspect of the tumor. Thin linear enhancement around the periphery of the fluid filled cavity may represent only post operative change at this stage. The lesion in relation to the left cerebral peduncle is unchanged. Slight increase in the extent of vasogenic edema within the left parietal and occipital lobes.
The patient went on to have surgery.
Histology:
MICROSCOPIC DESCRIPTION: The paraffin sections show fragments of cerebral cortex and white matter with non-specific reactive changes only. No evidence of tumor is seen. Paraffin sections of other samples show fragments of densely hypercellular astrocytic glioma. Tumor cells show moderate nuclear and cellular pleomorphism with spindle, epithelioid and gemistocytic forms noted. Frequent mitotic figures are identified and there are several foci of vascular endothelial hyperplasia. In addition, there are areas of both confluent and palisaded necrosis. Several of these areas contain thin walled necrotic and thrombosed blood vessels. The features are of glioblastoma multiforme.
FINAL DIAGNOSIS: Glioblastoma
Note: IDH mutation status is not provided in this case and according to the current (2016) WHO classification of CNS tumors, this tumor would, therefore, be designated as a glioblastoma NOS.
A two-week post-operative scan was taken to assist with adjuvant therapy treatment planning.
Left parieto-occipital craniotomy with an underlying surgical cavity containing fluid and locules of gas. In addition however, there is a ring enhancing mass adjacent to the cavity measuring 4cm in diameter compressing the posterior horn of the left lateral ventricle and surrounded with vasogenic edema. Second ring enhancing lesion in relation to the left cerebral peduncle is noted.
The patient returned to his home country following surgery and unfortunately, has since been lost to follow-up.
Case Discussion
Glioblastoma multiforme (GBM), or glioblastoma, is the most common primary brain malignancy accounting for 15-20% of all intracranial neoplasms 1. They are subdivided into astrocytomas and oligodendrogliomas, with the former being the most common type of glioma 2. It is one of the most biologically aggressive tumors, and despite management options of surgical resection, radiation therapy, chemotherapy, over 75% of patients die within 18 months 3.
GBMs arise in white matter, infiltrate along white matter tracts and perivascular spaces, and are characterized by a solitary and large irregularly shaped mass with associated necrosis and neovascularity 4. Typical histopathological features include cellular polymorphism, increased mitotic activity, atypical nuclei, vascular thrombosis and microvascular proliferation as well as necrosis 5.
Imaging is an integral component for clinical diagnosis, evaluation, treatment planning, and assessing the response to treatment/therapy. On CT imaging, GBMs are characterized by a hypointense lesion with surrounding vasogenic edema causing marked mass effect. There is intense irregular, heterogenous enhancement of the tumor margins with a hypointense center, representing necrosis 3,4.
MR imaging is crucial in tumor characterization. Lesions are typically hypo-intense on T1 weighted images and hyperintense on T2 weighted images and FLAIR 3,4. With intravenous contrast administration, findings include irregular and nodular rim enhancement with central hypo-intensity (interpreted as necrosis), Ill-defined margins and extensive surrounding hyperintensity corresponding to edema 6. Metabolic information may be acquired using MR spectroscopy where there is typically a reduction in NAA (N-acetylaspartate) corresponding to a decreased density of neuronal cells and increased choline as a result of higher cell membrane turnover 4.
Case courtesy of Associated Professor Pramit Phal
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