Answer for BIR CoW 27 Mar 2022
Meckel's cave meningioma
Findings
Evidence of well defined dumb-bell shaped T1 hypointense, T2 hyperintense extra axial lesion seen in left cerebellopontine angle, extending via the left porus trigeminus, into the left temporal region. The lesion shows no diffusion restriction or blooming foci. The inner component of the lesion measures 4.1 x 4.3 x 2.08 cm, and causes extrinsic compression of left side of midbrain and pons, encasing the terminal basilar artery, left superior cerebellar and left posterior cerebral arteries. The outer lesion measures 3.3 x 3.06 x 2.8 cm and causes compression over left medial temporal lobe. Left trigeminal nerve not separately visualised. ASL Perfusion shows significantly increased cerebral blood flow On contrast administration, the lesion shows intense contrast enhancement. IMPRESSION Avidly enhancing lesion involving left Meckel’s cave and extending to left cerebello pontine angle, causing relative luminal narrowing of left cavernous ICA - Possibility of Meckel’s cave meningioma Histopathology: Meningothelial meningioma – Grade 1
Discussion
Meningiomas are the most common extra-axial brain neoplasms, accounting for approximately 30% of all primary intracranial tumors. They are a non-glial neoplasm that originate from the meningocytes or arachnoid cap cells of the meninges and are located anywhere meninges are found, and in some places where only rest cells are presumed to be located. Although most meningiomas are grade I benign tumors, up to 20% are atypical (grade II) or anaplastic (grade III). Metastatic disease is rare but has been reported. Most common presentations include headache, paresis and change in mental status. Meningiomas originating in Meckel's cave (MC) are uncommon lesions that represent 1% of all intracranial meningiomas. In the 5th Edition (2021) WHO classification of CNS tumors a total of 15 subtypes of meningioma are recognized. Meningothelial meningiomas (also known as syncytial or endothelial meningiomas) are the most common histological subtype of meningioma, found in ~60% of all meningiomas, most frequently combined with fibrous meningioma (40%) or in isolation (17%). MRI is the investigation of choice for the diagnosis and characterization of meningiomas. They typically appear as extra-axial masses with a broad dural base and usually homogeneous and well-circumscribed, although many variants are encountered. Typical meningiomas appear isointense to grey matter on both T1 and T2 weighted images, enhancing vividly on both MRI and CT. MR spectroscopy usually does not play a significant role in diagnosis but can help distinguish meningiomas from mimics. Features include increase in alanine (1.3-1.5 ppm), glutamine/glutamate, increased choline (cellular tumor), absent or significantly reduced N-acetylaspartate (non-neuronal origin), absent or significantly reduced creatine. The differential diagnosis generally include other dural masses like solitary fibrous tumors of the dura, dural metastases. Treatment is usually with surgical excision. If only incomplete resection is possible (especially at the base of the skull) then external-beam radiation therapy (or even brachytherapy) can be used. Radiation has been shown to improve local control and prolongs overall survival.
REFERENCES:
1. Riemenschneider MJ, Perry A, Reifenberger G. Histological classification and molecular genetics of meningiomas. Lancet Neurol 2006;5(12):1045–1054.
2. Louis DN, Ohgaki H, Wiestler ODet al.. The 2007 WHO classification of tumours of the central nervous system. Acta Neuropathol (Berl) 2007;114(2):97–109.
3. Chandler, William F., Sandler, Howard M. 1956-. Brain Tumors. (1999) ISBN: 019512958X
4. Mendenhall W, Friedman W, Amdur R, Foote K. Management of Benign Skull Base Meningiomas: A Review. Skull Base. 2004;14(1):53-60. doi:10.1055/s-2004-821364
5. Walcott BP, Nahed BV, Brastianos PK et-al. Radiation Treatment for WHO Grade II and III Meningiomas. Front Oncol. 2013;3: 227. doi:10.3389/fonc.2013.00227.
Findings
Evidence of well defined dumb-bell shaped T1 hypointense, T2 hyperintense extra axial lesion seen in left cerebellopontine angle, extending via the left porus trigeminus, into the left temporal region. The lesion shows no diffusion restriction or blooming foci. The inner component of the lesion measures 4.1 x 4.3 x 2.08 cm, and causes extrinsic compression of left side of midbrain and pons, encasing the terminal basilar artery, left superior cerebellar and left posterior cerebral arteries. The outer lesion measures 3.3 x 3.06 x 2.8 cm and causes compression over left medial temporal lobe. Left trigeminal nerve not separately visualised. ASL Perfusion shows significantly increased cerebral blood flow On contrast administration, the lesion shows intense contrast enhancement. IMPRESSION Avidly enhancing lesion involving left Meckel’s cave and extending to left cerebello pontine angle, causing relative luminal narrowing of left cavernous ICA - Possibility of Meckel’s cave meningioma Histopathology: Meningothelial meningioma – Grade 1
Discussion
Meningiomas are the most common extra-axial brain neoplasms, accounting for approximately 30% of all primary intracranial tumors. They are a non-glial neoplasm that originate from the meningocytes or arachnoid cap cells of the meninges and are located anywhere meninges are found, and in some places where only rest cells are presumed to be located. Although most meningiomas are grade I benign tumors, up to 20% are atypical (grade II) or anaplastic (grade III). Metastatic disease is rare but has been reported. Most common presentations include headache, paresis and change in mental status. Meningiomas originating in Meckel's cave (MC) are uncommon lesions that represent 1% of all intracranial meningiomas. In the 5th Edition (2021) WHO classification of CNS tumors a total of 15 subtypes of meningioma are recognized. Meningothelial meningiomas (also known as syncytial or endothelial meningiomas) are the most common histological subtype of meningioma, found in ~60% of all meningiomas, most frequently combined with fibrous meningioma (40%) or in isolation (17%). MRI is the investigation of choice for the diagnosis and characterization of meningiomas. They typically appear as extra-axial masses with a broad dural base and usually homogeneous and well-circumscribed, although many variants are encountered. Typical meningiomas appear isointense to grey matter on both T1 and T2 weighted images, enhancing vividly on both MRI and CT. MR spectroscopy usually does not play a significant role in diagnosis but can help distinguish meningiomas from mimics. Features include increase in alanine (1.3-1.5 ppm), glutamine/glutamate, increased choline (cellular tumor), absent or significantly reduced N-acetylaspartate (non-neuronal origin), absent or significantly reduced creatine. The differential diagnosis generally include other dural masses like solitary fibrous tumors of the dura, dural metastases. Treatment is usually with surgical excision. If only incomplete resection is possible (especially at the base of the skull) then external-beam radiation therapy (or even brachytherapy) can be used. Radiation has been shown to improve local control and prolongs overall survival.
REFERENCES:
1. Riemenschneider MJ, Perry A, Reifenberger G. Histological classification and molecular genetics of meningiomas. Lancet Neurol 2006;5(12):1045–1054.
2. Louis DN, Ohgaki H, Wiestler ODet al.. The 2007 WHO classification of tumours of the central nervous system. Acta Neuropathol (Berl) 2007;114(2):97–109.
3. Chandler, William F., Sandler, Howard M. 1956-. Brain Tumors. (1999) ISBN: 019512958X
4. Mendenhall W, Friedman W, Amdur R, Foote K. Management of Benign Skull Base Meningiomas: A Review. Skull Base. 2004;14(1):53-60. doi:10.1055/s-2004-821364
5. Walcott BP, Nahed BV, Brastianos PK et-al. Radiation Treatment for WHO Grade II and III Meningiomas. Front Oncol. 2013;3: 227. doi:10.3389/fonc.2013.00227.
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!