Answer for BIR CoW 16 Jun 2024
OPTIC NERVE GLIOMA
Findings
Relatively well defined T1 hypointense, T2 / FLAIR hyperintense fusiform lesion noted in left optic nerve involving intraorbital, intracanalicular and intracranial segments upto optic chiasm associated with tortuosity showing no diffusion restriction/ gradient blooming. Mild proptosis of left globe noted. On contrast administration, the lesion shows relatively homogenous enhancement of the lesion with intraorbital segment showing peripheral enhancement.
Discussion
Optic nerve gliomas are well-differentiated, slowly growing intraconal tumors, with predilection for children in the first decade of life. It is the most common primary neoplasm of the optic nerve. The optic chiasm, optic tracts, and optic radiations can be involved. The tumors are usually benign in children and aggressive in adults; 90% present before age 20. Adults can get optic nerve glioblastomas, whereas optic gliomas are a disease of childhood and neurofibromatosis type 1 (NF1). It is usually unilateral except in patients with NF1; up to 20% of patients with NF1 have optic gliomas. It have a benign juvenile pilocytic histology. Clinically, optic nerve glioma presents as a low-grade proptosis, impaired vision, visual field obscuration with reduced eye movements, and optic atrophy. Growth of the tumor usually leads to fusiform enlargement of the optic nerve. MRI is better than CT for evaluating the optic nerve, optic chiasm, and optic radiations. MRI shows tubular or fusiform enlargement of the optic nerve, with kinking or buckling. Optic gliomas are typically isointense to cortex and hypointense to white matter and orbital fat on T1; they are isointense to hyperintense relative to white matter and the cortex on T2; intense enhancement is common, although optic nerve glioblastomas in adults may only minimally enhance as they are low grade astrocytomas. The bony optic canal may be widened if the intracanalicular segment of the nerve is involved. If associated with NF1, hyperintense lesions can be seen in the cerebellum, brain stem, basal ganglia, thalamus, periventricular white matter, and corpus callosum without mass effect, edema, or enhancement Optic glioma can be diagnosed with a high degree of confidence when it involves the optic chiasm and retrochiasmatic optic pathway. Although MRI is the ideal imaging modality to evaluate the optic nerve, CT is better at showing erosion or expansion of the optic canal. The primary differential diagnostic consideration is Meningioma, characterized by peripheral enhancement of the optic nerve sheath (“tram-track” sign), whereas enhancement of optic gliomas is more uniform. Calcification, seen in meningiomas but not gliomas, is best seen on CT
Findings
Relatively well defined T1 hypointense, T2 / FLAIR hyperintense fusiform lesion noted in left optic nerve involving intraorbital, intracanalicular and intracranial segments upto optic chiasm associated with tortuosity showing no diffusion restriction/ gradient blooming. Mild proptosis of left globe noted. On contrast administration, the lesion shows relatively homogenous enhancement of the lesion with intraorbital segment showing peripheral enhancement.
Discussion
Optic nerve gliomas are well-differentiated, slowly growing intraconal tumors, with predilection for children in the first decade of life. It is the most common primary neoplasm of the optic nerve. The optic chiasm, optic tracts, and optic radiations can be involved. The tumors are usually benign in children and aggressive in adults; 90% present before age 20. Adults can get optic nerve glioblastomas, whereas optic gliomas are a disease of childhood and neurofibromatosis type 1 (NF1). It is usually unilateral except in patients with NF1; up to 20% of patients with NF1 have optic gliomas. It have a benign juvenile pilocytic histology. Clinically, optic nerve glioma presents as a low-grade proptosis, impaired vision, visual field obscuration with reduced eye movements, and optic atrophy. Growth of the tumor usually leads to fusiform enlargement of the optic nerve. MRI is better than CT for evaluating the optic nerve, optic chiasm, and optic radiations. MRI shows tubular or fusiform enlargement of the optic nerve, with kinking or buckling. Optic gliomas are typically isointense to cortex and hypointense to white matter and orbital fat on T1; they are isointense to hyperintense relative to white matter and the cortex on T2; intense enhancement is common, although optic nerve glioblastomas in adults may only minimally enhance as they are low grade astrocytomas. The bony optic canal may be widened if the intracanalicular segment of the nerve is involved. If associated with NF1, hyperintense lesions can be seen in the cerebellum, brain stem, basal ganglia, thalamus, periventricular white matter, and corpus callosum without mass effect, edema, or enhancement Optic glioma can be diagnosed with a high degree of confidence when it involves the optic chiasm and retrochiasmatic optic pathway. Although MRI is the ideal imaging modality to evaluate the optic nerve, CT is better at showing erosion or expansion of the optic canal. The primary differential diagnostic consideration is Meningioma, characterized by peripheral enhancement of the optic nerve sheath (“tram-track” sign), whereas enhancement of optic gliomas is more uniform. Calcification, seen in meningiomas but not gliomas, is best seen on CT
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!