Answer:
Differential Diagnosis : 1. Trigeminal schwanoma 2. Lymphoma 3. Meningioma 4.Orbital Pseudotumour
HPE : Schwannoma
Findings:
T1 isointense T2 hypointense enhancing mass centered in the right meckels cave and extending to the CP Angle in the posterior cranial fossa and anteriorly in to the orbit thro the superior orbital fissure. It displaces the ICA medially in the cavernous sinus, laterally causes mass effect and edema in the temporal lobe. the foramen ovale ( mandibular division of CN V), rotundum(maxillary division) and inferior orbital fissur are widenened by the mass.
Discussion:
There are no hyperintense signal in T2 which is usually expected in a schwanoma . However Antoni type A tissue has elongated spindle cells arranged in irregular streams and is compact in nature ( hence explains the T2 hypointensity), type B tissue has a looser organization, often with cystic spaces intermixed within the tissue. The cystic spaces can result in high signal intensity on T2-weighted MRIs.
Differential Diagnosis : 1. Trigeminal schwanoma 2. Lymphoma 3. Meningioma 4.Orbital Pseudotumour
HPE : Schwannoma
Findings:
T1 isointense T2 hypointense enhancing mass centered in the right meckels cave and extending to the CP Angle in the posterior cranial fossa and anteriorly in to the orbit thro the superior orbital fissure. It displaces the ICA medially in the cavernous sinus, laterally causes mass effect and edema in the temporal lobe. the foramen ovale ( mandibular division of CN V), rotundum(maxillary division) and inferior orbital fissur are widenened by the mass.
Discussion:
There are no hyperintense signal in T2 which is usually expected in a schwanoma . However Antoni type A tissue has elongated spindle cells arranged in irregular streams and is compact in nature ( hence explains the T2 hypointensity), type B tissue has a looser organization, often with cystic spaces intermixed within the tissue. The cystic spaces can result in high signal intensity on T2-weighted MRIs.