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| Discussion |
Case Report:
A 20-year-old male, came with history of headache, vomiting and altered sensorium with mild left sided weakness in June 2008.
A plain and contrast enhanced CT scan done at another center had revealed a hypodense, enhancing lesions that had been interpreted to represent tuberculomas (Fig 1 and 2). The patient was then treated with anti tuberculous treatment for 4 months with no further complaints. In November 2008, the patient developed left sided weakness (Gr. 1,2).
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Fig. 1 |
Fig. 2 |
At this time, a repeat plain CT scan done elsewhere had shown moderate right frontotemporoparietal hematoma with compression of the ipsilateral lateral ventricle and ambient cistern and midline shift with subfalcine herniation and increase in the size of the lesion. (Fig 3).
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Fig. 3 |
On conservative treatment, his weakness improved gradually and a plain follow-up CT in Dec ’08 had shown gradual resolution of the hematoma with cystic change (Fig 4)
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Fig. 4 |
The lesion was suspected to be an abscess, and accordingly the cystic component was aspirated Dec ’08. It showed increased protein content. No pus cells or organism nor malignant cells were detected.
The patient again developed severe left sided weakness (power 1-2) with motor aphasia in Jan '09.
A repeat CT scan at another center in February ’09, has shown an increase in the size of the lesion with blood in various stages of degradation and cystic change and post contrast enhancement (Fig 5)
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Fig. 5 |
He was then referred to this institution and an MRI was done performed.
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Fig. 6 |
Fig. 7 |
This study showed an increase in the size of the lesion with intralesional bleed and cystic changes and perilesional edema. MR perfusion showed minimal perfusion of the tumor. MR spectroscopy was not helpful due to the increased noise caused by the blood and cystic areas. The radiological differential diagnosis considered were of neoplasm with hemorrhage or a resistant tuberculoma with a bleeding mycotic aneurysm was given, the former being more likely.
An angiogram performed at this time showed a minimally vascular lesion in the right fronto – temporo – parietal region with displacement of the Sylvian triangle and medial displacement of the lenticulostriate arteries. No pseudoaneurysm was seen. (Fig 8)
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Fig. 8 |
He underwent excision biopsy in March ’09 with the frozen section and histopathology report being of glioblastoma multiforme.
A post operative MRI showed complete excision of the tumor with pachymeningeal enhancement seen in the right temporal region (Fig 9).
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Fig. 9 |
Currently, the patient is asymptomatic with normal power (4+ to 5).
Glioblastoma multiforme is the most common of all primary brain tumors, and forms about half of all cerebral astrocytomas. It is unfortunately the most malignant form of astrocytoma.
Clinical features - The patient usually presents with symptoms of intracranial SOL or of raised ICT, including headache, seizures or focal neurological deficits.
Pathology - As the name suggests, the tumor shows a variegated appearance, with areas of hemorrhage, cystic degeneration, necrosis and neoangiogenesis being common. Histological picture again varies from relatively well-differentiated foci to bizarre pleomorphic or undifferentiated cells. It is highly malignant and spreads along the white matter tracts, ependyma, subarachnoid space and pial surface. Intracranial metastases are common, but extracranial metastases and bone invasion are rare. CT and MRI are the prime modalities of diagnosis.
Imaging features :
CT- Glioblastomas usually appear as irregularly shaped hypodense lesions with a irregular rim enhancement and perilesional cerebral edema. Intratumoral heterogeneity is present, with areas of necrosis, cyst formation and hemorrhage being common. They are often bihemispheric (butterfly shaped).
MRI– It shows aring enhancing lesion with a perilesional edema, with areas of necrosis and hemorrhage of different ages within. There is usually marked but inhomogenous post contrast enhancement. MR perfusion shows increased perfusion. MR spectroscopy demonstrates an increase in the choline-to-creatine peak ratio, an increased lactate peak, and decreased N- acetylaspartate (NAA) peak in areas with glioblastomas.
Angiography– It shows tumor blush, contrast stasis or pooling in bizarre vascular channels in most cases. AV shunting may be present.
Treatment – Surgery is the primary modality of treatment. However, glioblastoma is highly malignant and most tumors metastasize or recur. 5 year survival rates are essentially zero.
CONCLUSION :
The variegated appearance of the lesion, with hemorrhagic and cystic areas, its rapid increase in size in a relatively short span of time, and non-responsiveness to anti tuberculous treatment were all indications of the malignant process. An earlier performed MRI instead of the serial follow-up with CT scans would have probably detected the tumor earlier.
Tuberculomas almost invariably show single or conglomerate ring enhancement. Intralesional bleed is rare in the case of a tuberculoma, and points to another process. The increasing size of the lesion inspite of ATT given was another indication of the lesion being more likely to be malignant.