Answer for BIR CoW 12 Mar 2023
BILATERAL THALAMIC GLIOMA
Findings
Well defined non enhancing T1 hypo, T2/ FLAIR hyperintense lesions involving bilateral thalamus showing patchy areas of diffusion restriction with no blooming foci within . ASL – reveals mildly increased perfusion of the thalamic lesions MRS – increased choline , reduced NAA integral values and elevated Cho/NAA ratio
Discussion
Bilateral thalamic gliomas are rare but characteristic low-grade astrocytomas that occur in children and young adults Young children with bilateral thalamic glioma often have signs of increased intracranial pressure and movement disorders, while older children and adults often experience mental deterioration with behavioral impairment such as personality changes or dementia. Classical morphological features of these lesions are diffuse symmetrical enlargement of the thalamic nuclei and the absence of bridging tumour between the two . They typically involve the dorsomedial and intralaminar nuclei of the thalami and often spare the adjoining third ventricle, temporal lobes, midbrain and pineal gland until late stages of the disease On imaging, BTG is characterized by diffuse swelling of bilateral thalami with homogenously hypodense attenuation on CT. On MRI enlarged bilateral thalami show homogenous hypointense or isointense signal intensity on T1-W and hyperintense signal intensity on T2-W images. No contrast enhancement is seen on postcontrast enhanced CT or MRI. These features are characteristic of a diffuse low-grade astrocytoma. Histological higher grade tumors (anaplastic type) may show some enhancement on contrast-enhanced CT/MRI. MR spectroscopy shows reduced N-acetylaspartate peak in the tumor with variably elevated choline and myoinositol peaks. It may show classic elevated creatine/phosphocreatine peak which might be typical for a glioma at the thalamic location. Treatment options are limited, with surgical resection precluded by the vitality of the structures involved. In cases with associated obstructive hydrocephalus, cerebrospinal fluid diversion may offer symptomatic relief of elevated intracranial pressure but does not otherwise alter the course of the disease. The role of radiation and chemotherapy, in conjunction or individually, remains a subject of debate . Factors associated with overall survival include tumor grade and duration of symptoms between onset and diagnosis, with lower tumor grade and duration of symptoms between onset and diagnosis of more than two months both associated with an increased overall survival time.
REFERENCES:
Silveira L, Allison D, Delahmetovic E, Muse J, Penar P. Bilateral Thalamic Glioma: A Case Report. Cureus. 2021 Nov 14;13(11):e19570. doi: 10.7759/cureus.19570. PMID: 34926042; PMCID: PMC8671068. Bilateral Thalamic Lesions. Alice B. Smith, Smirniotopoulos, Elisabeth J. Rushing, and Steven J. Goldstein. American Journal of Roentgenology 2009 192:2, W53-W62. Estève, François et al "MR Spectroscopy of Bilateral Thalamic Gliomas." American Journal of Neuroradiology 20.5 (1999): 876-881. Web. 09 Mar. 2023.
Findings
Well defined non enhancing T1 hypo, T2/ FLAIR hyperintense lesions involving bilateral thalamus showing patchy areas of diffusion restriction with no blooming foci within . ASL – reveals mildly increased perfusion of the thalamic lesions MRS – increased choline , reduced NAA integral values and elevated Cho/NAA ratio
Discussion
Bilateral thalamic gliomas are rare but characteristic low-grade astrocytomas that occur in children and young adults Young children with bilateral thalamic glioma often have signs of increased intracranial pressure and movement disorders, while older children and adults often experience mental deterioration with behavioral impairment such as personality changes or dementia. Classical morphological features of these lesions are diffuse symmetrical enlargement of the thalamic nuclei and the absence of bridging tumour between the two . They typically involve the dorsomedial and intralaminar nuclei of the thalami and often spare the adjoining third ventricle, temporal lobes, midbrain and pineal gland until late stages of the disease On imaging, BTG is characterized by diffuse swelling of bilateral thalami with homogenously hypodense attenuation on CT. On MRI enlarged bilateral thalami show homogenous hypointense or isointense signal intensity on T1-W and hyperintense signal intensity on T2-W images. No contrast enhancement is seen on postcontrast enhanced CT or MRI. These features are characteristic of a diffuse low-grade astrocytoma. Histological higher grade tumors (anaplastic type) may show some enhancement on contrast-enhanced CT/MRI. MR spectroscopy shows reduced N-acetylaspartate peak in the tumor with variably elevated choline and myoinositol peaks. It may show classic elevated creatine/phosphocreatine peak which might be typical for a glioma at the thalamic location. Treatment options are limited, with surgical resection precluded by the vitality of the structures involved. In cases with associated obstructive hydrocephalus, cerebrospinal fluid diversion may offer symptomatic relief of elevated intracranial pressure but does not otherwise alter the course of the disease. The role of radiation and chemotherapy, in conjunction or individually, remains a subject of debate . Factors associated with overall survival include tumor grade and duration of symptoms between onset and diagnosis, with lower tumor grade and duration of symptoms between onset and diagnosis of more than two months both associated with an increased overall survival time.
REFERENCES:
Silveira L, Allison D, Delahmetovic E, Muse J, Penar P. Bilateral Thalamic Glioma: A Case Report. Cureus. 2021 Nov 14;13(11):e19570. doi: 10.7759/cureus.19570. PMID: 34926042; PMCID: PMC8671068. Bilateral Thalamic Lesions. Alice B. Smith, Smirniotopoulos, Elisabeth J. Rushing, and Steven J. Goldstein. American Journal of Roentgenology 2009 192:2, W53-W62. Estève, François et al "MR Spectroscopy of Bilateral Thalamic Gliomas." American Journal of Neuroradiology 20.5 (1999): 876-881. Web. 09 Mar. 2023.
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!