Answer for BIR CoW 14 Feb 2021
ANAPLASTIC ASTROCYTOMA WITH LEPTOMENINGEAL AND SUBARACHNOID SPREAD
Findings
• Ill defined t1 isointense, t2 hyperintense lesion noted involving body and genu of corpus callosum, cingulate gyrus and adjacent frontal lobe in midline, infiltrating left gc structures . • there is diffusion restriction and significantly low adc values noted within the lesion. • on contrast there is mild patchy enhancement noted . • evidence of large ill defined, irregular, mixed intensity lesion noted in the extradural plane in left frontoparietal and temporal region causing compression of adjacent brain parenchyma. • the lesion has solid and cystic components and the solid component shows gradient blooming and restricted diffusion. • it measures 10.9 (ap) x 4.8 (tr) x 5 (cc) cm. • there is subarachnoid spread involving left sylvian cistern, suprachiasmatic cistern, perimesencephalic cistern, quadrigeminal cistern, bilateral cerbellopontine angle cistern and prepontine cistern. • multiple blooming foci noted in cerebellar foliae on both sides – suggestive of leptomeningeal spread. • on contrast heterogenous enhancement noted within the solid components.
Discussion
Anaplastic astrocytoma is a rare malignant brain tumor. Astrocytomas are tumors that develop from certain star-shaped brain cells called astrocytes. Anaplastic astrocytomas are grade III astrocytomas Anaplastic astrocytomas occur in adulthood with a peak incidence between 40 and 50 years of age, which is older than low-grade astrocytomas and younger than glioblastomas Anaplastic astrocytomas appear similar to low-grade astrocytomas but are more variable in appearance and a single tumour demonstrates more heterogeneity. The key to distinguishing anaplastic astrocytomas from low-grade tumours is the presence of enhancement which should be absent in the latter (although one should note that variants, especially gemistocytic astrocytomas, can demonstrate enhancement). The pattern of enhancement is very variable. Unlike glioblastomas, anaplastic astrocytomas lack frank necrosis, and as such central non-enhancing fluid intensity regions should be absent 1. • T1: hypointense compared to white matter • T2: generally hyperintense but can be heterogeneous in cases with blood calcification • T2-FLAIR: relative hypointensity of most of the tumour except a hyperintense rim (T2-FLAIR mismatch sign) • T1 C+ (Gd) o very variable but usually at least some enhancement is present o presence of ring enhancement suggests central necrosis and thus glioblastoma rather than anaplastic astrocytoma • MR spectroscopy o increased choline-to-creatine ratio o NAA preserved or mildly depressed o no significant lactate o intermediate levels of myo-inositol (lower than low grade, but higher than GBM)
Findings
• Ill defined t1 isointense, t2 hyperintense lesion noted involving body and genu of corpus callosum, cingulate gyrus and adjacent frontal lobe in midline, infiltrating left gc structures . • there is diffusion restriction and significantly low adc values noted within the lesion. • on contrast there is mild patchy enhancement noted . • evidence of large ill defined, irregular, mixed intensity lesion noted in the extradural plane in left frontoparietal and temporal region causing compression of adjacent brain parenchyma. • the lesion has solid and cystic components and the solid component shows gradient blooming and restricted diffusion. • it measures 10.9 (ap) x 4.8 (tr) x 5 (cc) cm. • there is subarachnoid spread involving left sylvian cistern, suprachiasmatic cistern, perimesencephalic cistern, quadrigeminal cistern, bilateral cerbellopontine angle cistern and prepontine cistern. • multiple blooming foci noted in cerebellar foliae on both sides – suggestive of leptomeningeal spread. • on contrast heterogenous enhancement noted within the solid components.
Discussion
Anaplastic astrocytoma is a rare malignant brain tumor. Astrocytomas are tumors that develop from certain star-shaped brain cells called astrocytes. Anaplastic astrocytomas are grade III astrocytomas Anaplastic astrocytomas occur in adulthood with a peak incidence between 40 and 50 years of age, which is older than low-grade astrocytomas and younger than glioblastomas Anaplastic astrocytomas appear similar to low-grade astrocytomas but are more variable in appearance and a single tumour demonstrates more heterogeneity. The key to distinguishing anaplastic astrocytomas from low-grade tumours is the presence of enhancement which should be absent in the latter (although one should note that variants, especially gemistocytic astrocytomas, can demonstrate enhancement). The pattern of enhancement is very variable. Unlike glioblastomas, anaplastic astrocytomas lack frank necrosis, and as such central non-enhancing fluid intensity regions should be absent 1. • T1: hypointense compared to white matter • T2: generally hyperintense but can be heterogeneous in cases with blood calcification • T2-FLAIR: relative hypointensity of most of the tumour except a hyperintense rim (T2-FLAIR mismatch sign) • T1 C+ (Gd) o very variable but usually at least some enhancement is present o presence of ring enhancement suggests central necrosis and thus glioblastoma rather than anaplastic astrocytoma • MR spectroscopy o increased choline-to-creatine ratio o NAA preserved or mildly depressed o no significant lactate o intermediate levels of myo-inositol (lower than low grade, but higher than GBM)
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!