Answer for BIR CoW 28 Dec 2025
Pilomyxoid astrocytoma causing obstructive hydrocephalus
Findings
Relatively defined T1 hypointense, T2 / FLAIR heterointense solid cystic lesion noted in sellar and suprasellar region measuring 5 x 3.5 x 4.6 cm, showing patchy diffusion restriction and gradient blooming. Superiorly the lesion causes mass effect over roof of 3rd ventricle causing dilated bilateral lateral ventricles. The lesion is noted involving optic chiasma, infundibulum and intracranial and intracanalicular part of bilateral optic nerve anteriorly extending into left basifrontal and left anterior temporal region laterally and posteriorly into prepontine cistern. Inferiorly,the lesion causes compression of pituitary gland. On contrast administration, the lesion shows heterogenous enhancement. DIAGNOSIS- Pilomyxoid astrocytoma(Biopsy proven) causing obstructive hydrocephalus
Discussion
Pilomyxoid astrocytoma (PMA) is a rare primary central nervous system (CNS) tumor recently described as a histologic variant of pilocytic astrocytoma (PA) PMA has a strong geographic predilection for the hypothalamic/chiasmatic region, however, they may also occur elsewhere within the brain These tumors are usually large, well-circumscribed, lobulated and may have solid or cystic components with no or minimal surrounding edema. They are typically described as H-shaped as they expand from the midline (hypothalamic and optic chiasm region) into both temporal lobes. Hemorrhagic components and CSF dissemination can also be seen. A younger age, more frequent occurrence at the suprasellar area, mainly solid mass containing non-enhancing portion, and more frequent leptomeningeal dissemination are helpful differential features of PMAs as compared to PAs.
References
1.Pilomyxoid Astrocytoma: Expanding the Imaging Spectrum L.L. Linscott, A.G. Osborn, S. Blaser, M. Castillo, R.H. Hewlett, N. Wieselthaler, S.S. Chin, J. Krakenes, G.L. Hedlund and C.L. Sutton American Journal of Neuroradiology November 2008 2.Imaging characteristics of pilomyxoid astrocytomas in comparison with pilocytic astrocytomas In Ho Leea,d [email protected] ∙ Ji Hye Kima [email protected] ∙ Yeon-Lim Suhb [email protected] ∙
Findings
Relatively defined T1 hypointense, T2 / FLAIR heterointense solid cystic lesion noted in sellar and suprasellar region measuring 5 x 3.5 x 4.6 cm, showing patchy diffusion restriction and gradient blooming. Superiorly the lesion causes mass effect over roof of 3rd ventricle causing dilated bilateral lateral ventricles. The lesion is noted involving optic chiasma, infundibulum and intracranial and intracanalicular part of bilateral optic nerve anteriorly extending into left basifrontal and left anterior temporal region laterally and posteriorly into prepontine cistern. Inferiorly,the lesion causes compression of pituitary gland. On contrast administration, the lesion shows heterogenous enhancement. DIAGNOSIS- Pilomyxoid astrocytoma(Biopsy proven) causing obstructive hydrocephalus
Discussion
Pilomyxoid astrocytoma (PMA) is a rare primary central nervous system (CNS) tumor recently described as a histologic variant of pilocytic astrocytoma (PA) PMA has a strong geographic predilection for the hypothalamic/chiasmatic region, however, they may also occur elsewhere within the brain These tumors are usually large, well-circumscribed, lobulated and may have solid or cystic components with no or minimal surrounding edema. They are typically described as H-shaped as they expand from the midline (hypothalamic and optic chiasm region) into both temporal lobes. Hemorrhagic components and CSF dissemination can also be seen. A younger age, more frequent occurrence at the suprasellar area, mainly solid mass containing non-enhancing portion, and more frequent leptomeningeal dissemination are helpful differential features of PMAs as compared to PAs.
References
1.Pilomyxoid Astrocytoma: Expanding the Imaging Spectrum L.L. Linscott, A.G. Osborn, S. Blaser, M. Castillo, R.H. Hewlett, N. Wieselthaler, S.S. Chin, J. Krakenes, G.L. Hedlund and C.L. Sutton American Journal of Neuroradiology November 2008 2.Imaging characteristics of pilomyxoid astrocytomas in comparison with pilocytic astrocytomas In Ho Leea,d [email protected] ∙ Ji Hye Kima [email protected] ∙ Yeon-Lim Suhb [email protected] ∙
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!