Post-ictal changes presenting as late pseudoprogression on MRI and PET in a patient with diffuse glioma: Case report and brief literature review.

Following completion of adjuvant radiation and chemotherapy imaging surveillance forms a major role in the management of diffuse gliomas. The primary role of imaging is to detect recurrences earlier than clinical symptomatology. Magnetic resonance imaging (MRI) is considered the gold standard in follow-up protocols owing to better soft tissue delineation and multiparametric nature. True recurrence can often mimic treatment-related changes, it is of paramount importance to differentiate between the two entities as the clinical course is divergent. Addition of functional sequences like perfusion, spectroscopy and metabolic imaging can provide further details into the microenvironment. In equivocal cases, a follow-up short interval imaging might be obtained to settle the diagnostic dilemma. Here, we present a patient with diagnosis of recurrent oligodendroglioma treated with adjuvant chemoradiation, presenting with seizures five years post-completion of chemotherapy for recurrence. On MRI, subtle new onset gyral thickening of the left frontal region with mild increase in perfusion and patchy areas of raised choline. FET-PET (fluoro-ethyltyrosine) showed an increased tumour-to-white matter (T/Wm) ratio favouring tumour recurrence. Based on discussion in a multi-disciplinary joint clinic, short interval follow-up MRI was undertaken at two months showing decrease in gyral thickening and resolution of enhancing areas in left frontal lobe. Repeat imaging one year later demonstrated stable disease status without further new imaging findings. Given the changes resolving completely without any anti-tumoral intervention, we conclude this to be peri-ictal pseudoprogression, being the second such case described in India.

Surveillance imaging frequency in adult patients with lower-grade (WHO Grade 2 and 3) gliomas.

With improved outcome following aggressive treatment in patients with grade 2 and 3 IDH-mutant (IDHmt), 1p/19q codeleted oligodendroglioma and IDHmt, non-codeleted astrocytoma, prolonged surveillance is desirable for early detection of tumor growth and malignant transformation. Current National Comprehensive Cancer Network (NCCN) guidelines provide imaging follow-up recommendations based on molecular classification of lower-grade gliomas, although individualized imaging guidelines based on treatments received and after tumor recurrence are not clearly specified. Other available guidelines have yet to incorporate the molecular biomarkers that inform the WHO classification of gliomas, and in some cases do not adequately consider current knowledge on IDHmt glioma growth rate and recurrence patterns. Moreover, these guidelines also do not provide specific recommendations for concerning clinical symptoms or radiographic findings warranting imaging studies out of prespecified intervals. Focusing on molecularly defined grade 2 and 3 IDHmt astrocytomas and oligodendrogliomas, we review current knowledge of tumor growth rates and time to tumor progression for each tumor type and propose a range of recommended MRI surveillance intervals for both the newly diagnosed and recurrent tumor setting. Additionally, we summarize situations in which imaging is advisable outside of these intervals.

Thalamic gliomas in children: an extensive clinical, neuroradiological and pathological study of 14 cases.

OBJECT: Thalamic tumors represent only 1 to 5% of brain neoplasms but frequently affect children. However, pediatric series are rare and go back to several years in spite of recent advances in the neuroradiological, pathological, and molecular fields. METHODS: We report a series of 14 pediatric thalamic gliomas with clinical, neuroradiological, and pathological studies including p53 immunostaining in 11 cases and 1p19q status in three cases. RESULTS: Our series included five pilocytic astrocytomas, seven oligodendrogliomas, and two glioblastomas. Pilocytic astrocytomas were characterized by strong contrast enhancement, lack of p53 expression, and excellent prognosis. Oligodendrogliomas frequently demonstrated an aspect of unilateral thalamic enlargement lacking or with slight contrast enhancement. Some of them expressed p53 or demonstrated 1p loss. Anaplastic oligodendrogliomas and glioblastomas displayed a poor outcome, with a mean survival of 8 months after surgery. CONCLUSION: Our series of pediatric thalamic gliomas clearly distinguishes pilocytic astrocytomas from anaplastic oligodendrogliomas regarding neuroimaging, pathology, and prognosis.

Preclinical and clinical evaluation of O-[11C]methyl-L-tyrosine for tumor imaging by positron emission tomography.

We performed preclinical and clinical studies of O-[11C]methyl-L-tyrosine, a potential tracer for imaging amino acid transport of tumors by positron emission tomography (PET). Examinations of the radiation-absorbed dose by O-[11C]methyl-L-tyrosine and the acute toxicity and mutagenicity of O-methyl-L-tyrosine showed suitability of the tracer for clinical use. The whole-body imaging of monkeys and healthy humans by PET showed low uptake of O-[11C]methyl-L-tyrosine in all normal organs except for the urinary track and bladder, suggesting that the O-[11C]methyl-L-tyrosine PET has the potential for tumor imaging in the whole-body. Finally, the brain tumor imaging was preliminarily demonstrated.

[Uptake of DL-3-123I-iodo-alpha-methyltyrosine in recurrent brain tumors]. / Anreicherung von DL-3-123I-Jod-alpha-methyltyrosin in Hirntumorrezidiven.

DL-3-123I-iodo-alpha-methyltyrosine (123I-IMT) is a radiopharmacon which concentrates in brain tumors and can be employed in SPECT. We performed 20 studies in 16 patients after neurosurgery for malignant brain tumors (localization of the primary tumor by CT/MRI). Tumor/non-tumor ratios (T/NT) were calculated in ROI-technique. In 17 cases there was a recurrence or tumor remnant. 14/17 were detectable by increased uptake (T/NT 1.43-2.25). The scans were correlated with CT/MRI studies and validated by biopsy (6/14) or follow-up. All 3 patients without recurrence (neuroradiological follow-up over 6-24 months) had a negative scan. 123I-IMT scintigraphy provides complementary information to CT and MRI. In equivocal neuroradiological or clinical cases it may be valuable in the detection of tumor recurrences and allows an earlier onset of therapy.

Gyratory epilepsy in a patient with a thalamic neoplasm.

A patient with a right thalamic oligodendroglioma developed seizures characterized by circling behavior, speech arrest, and secondarily generalized seizures. Gyratory epilepsy is relatively uncommon and may either represent a benign form of primary generalized epilepsy or occur secondary to a focal cortical lesion. Thalamic stimulation has been shown experimentally to induce circling movements, but no other clinical cases with a thalamic lesion have been described.