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Figure 2: (a) Histological examination revealed a neoplasm with highly pleomorphic cells exhibiting several mitoses (arrows); (b) microvascular
proliferation was also evident, a common finding in high grade gliomas (arrows); (c) some areas of the biopsied tumor showed evidence of radiation-
induced changes, such as necrosis (arrows) and vascular changes such as telangiectasia and hyalinization of vessel walls adjacent to areas of
hypercellular tumor tissue (arrows); (d) the proliferation marker MIB1 (Ki67) was expressed in a high proportion of tumor cells (arrows).
choline (Cho) with ratio Cho/NAA > 3.63, compatible combination of radiotherapy with temozolomide
with infiltration of malignant cells with high metabolic chemotherapy followed by plain temozolomide
[3]
activity (not shown). Positron emission tomography therapy, glioblastoma multiforme usually recurs
[5]
(PET) scan was not available atour institution. within the first year from therapy. However, at that
point it may be difficult to differentiate between
Due to discrepancy between the imaging tests, a radiation necrosis of the tumor vs. tumor recurrence,
partial surgical resection was performed for accurate since both conditions behave similarly on traditional
diagnosis. Histological examination showed evidence imaging modalities (Standard CT or MRI with and
of tumor recurrence in most of the resected tissue without IV contrast administration). In these cases,
[6]
[Figure 2a and 2b]. There were some small parts of the more advanced imaging modalities can be employed
tumor exhibiting radiation-induced changes as well to differentiate between tumor recurrence from
[Figure 2c]. The high proliferation rate of the tumor radiation necrosis, such as PET and perfusion/
[7]
cells denoted an aggressive tumor [Figure 2d]. The diffusion MRI. However, in many countries, PET
[8]
patient was started on daily low dose temozolomide (50 is not widely available, necessitating the use of other
mg/m of body surface per os) administration and oral nuclear medicine modalities such as SPECT with
2
dexamethasone at 6 mg/day, and she remained alive various tracers. [9]
and stable 6 months after the operation.
MR spectroscopy is another alternative imaging
DISCUSSION method to improve our diagnostic capabilities in
brain tumor evaluation, however, this modality is
After the standard initial therapy, consisting of a still not widely available. NAA is an acetylated
[10]
Neuroimmunol Neuroinflammation | Volume 3 | July 8, 2016 163