Answer for BIR CoW 02 May 2021
RIGHT ETHMOIDAL MENINGIOMA
Findings
CT PNS- Expansile soft tissue lesion with multiple linear calcific septations noted involving right ethmoidal sinus with adjacent bony remodeling and thinning of right lamina papyracea, abutting, and laterally displacing the right medial rectus muscle. The lesion obstructing the right infundibulum causing right maxillary sinusitis. On contrast administration, the lesions show intense heterogeneous contrast enhancement. On MRI, the lesion is iso to hypointense on both T1 and T2 with low ADC values.
Discussion
Meningiomas are tumors of benign histological nature which represent 13 to 26% of all primary intracranial neoplasia. Primary extracranial meningiomas are histologically identical to intracranial meningiomas. They usually occur in 40 to 60-year-old patients and are rare in the pediatric age group. Primary extracranial meningiomas represent 1 to 2% of all meningiomas Primary extracranial meningioma of the Sinonasal cavity or paranasal sinuses is rare (<0.1%), especially in children. Meningioma is a tumor derived from meningocytes found in the meninges, in approximately 20% of cases it presents an extracranial extension due to continuity The primary origin of meningiomas at extracranial sites related to a) the presence of arachnoid cells in nerve sheaths or in vessels where they emerge from the central nervous system, b) the migration of tissue from the meninges to extracranial regions during embryogenesis, c) traumatic events or intracranial hypertension that displaces arachnoid cells and finally, d) undifferentiated mesenchymal cells Radiological characteristics are similar to typical meningioma on-contrast CT: 60% slightly hyperdense to normal brain, the rest are more isodense 20-30% have some calcification post-contrast CT 72% brightly and homogeneously contrast enhance malignant or cystic variants demonstrate more heterogeneity/less intense enhancement MRI: T1 - usually isointense to grey matter (60-90%) T2 usually isointense to grey matter (~50%) hyperintense to grey matter (35-40%) seen in the microcystic, secretory, cartilaginous (metaplastic) choroid and angiomatous variants hypointense to grey matter (10-15%): fibrous and calcific contents DWI – restricted diffusion The imaging characteristics of these sinonasal meningiomas are those of an enhancing, expansile mass with bone remodeling. Most lesions lie in the nasal vault, and adjacent sclerotic, reactive bone may be a dominant feature. This reactive bone may radiographically mimic fibrous dysplasia. On MR imaging, these tumors have signal intensities similar to those of the brain on all imaging sequences. When they occur within the nasal cavity, they may mimic a fibro-osseous lesion and there often is no meningeal enhancement on MR imaging
The prognosis is good. In cases of tumor recurrence, the tumor usually arises in the same anatomic site as the primary tumor and probably represents the residual disease rather than the recurrent tumor.
DIFFERENTIAL DIAGNOSIS: Sinonasal lymphoma Inverted papilloma Fibrous dysplasia
REFERENCE: 1. Primary Extracranial Meningioma of Paranasal Sinuses Ranjan G. Aiyer, V. Prashanth, corresponding author Kirti Ambani, Vadish S. Bhat, and Geeta B. Soni 2. Extracranial meningioma of the ethmoid sinus- Radiopaedia 3. Clinical-radiological aspects of primary extracranial meningioma of the ethmoid sinus in a child - Arq. Neuro-Psiquiatr. vol.66 no.2a São Paulo June 2008 4. Peter M. Som • Hugh D. Curtin- Head and Neck imaging
Findings
CT PNS- Expansile soft tissue lesion with multiple linear calcific septations noted involving right ethmoidal sinus with adjacent bony remodeling and thinning of right lamina papyracea, abutting, and laterally displacing the right medial rectus muscle. The lesion obstructing the right infundibulum causing right maxillary sinusitis. On contrast administration, the lesions show intense heterogeneous contrast enhancement. On MRI, the lesion is iso to hypointense on both T1 and T2 with low ADC values.
Discussion
Meningiomas are tumors of benign histological nature which represent 13 to 26% of all primary intracranial neoplasia. Primary extracranial meningiomas are histologically identical to intracranial meningiomas. They usually occur in 40 to 60-year-old patients and are rare in the pediatric age group. Primary extracranial meningiomas represent 1 to 2% of all meningiomas Primary extracranial meningioma of the Sinonasal cavity or paranasal sinuses is rare (<0.1%), especially in children. Meningioma is a tumor derived from meningocytes found in the meninges, in approximately 20% of cases it presents an extracranial extension due to continuity The primary origin of meningiomas at extracranial sites related to a) the presence of arachnoid cells in nerve sheaths or in vessels where they emerge from the central nervous system, b) the migration of tissue from the meninges to extracranial regions during embryogenesis, c) traumatic events or intracranial hypertension that displaces arachnoid cells and finally, d) undifferentiated mesenchymal cells Radiological characteristics are similar to typical meningioma on-contrast CT: 60% slightly hyperdense to normal brain, the rest are more isodense 20-30% have some calcification post-contrast CT 72% brightly and homogeneously contrast enhance malignant or cystic variants demonstrate more heterogeneity/less intense enhancement MRI: T1 - usually isointense to grey matter (60-90%) T2 usually isointense to grey matter (~50%) hyperintense to grey matter (35-40%) seen in the microcystic, secretory, cartilaginous (metaplastic) choroid and angiomatous variants hypointense to grey matter (10-15%): fibrous and calcific contents DWI – restricted diffusion The imaging characteristics of these sinonasal meningiomas are those of an enhancing, expansile mass with bone remodeling. Most lesions lie in the nasal vault, and adjacent sclerotic, reactive bone may be a dominant feature. This reactive bone may radiographically mimic fibrous dysplasia. On MR imaging, these tumors have signal intensities similar to those of the brain on all imaging sequences. When they occur within the nasal cavity, they may mimic a fibro-osseous lesion and there often is no meningeal enhancement on MR imaging
The prognosis is good. In cases of tumor recurrence, the tumor usually arises in the same anatomic site as the primary tumor and probably represents the residual disease rather than the recurrent tumor.
DIFFERENTIAL DIAGNOSIS: Sinonasal lymphoma Inverted papilloma Fibrous dysplasia
REFERENCE: 1. Primary Extracranial Meningioma of Paranasal Sinuses Ranjan G. Aiyer, V. Prashanth, corresponding author Kirti Ambani, Vadish S. Bhat, and Geeta B. Soni 2. Extracranial meningioma of the ethmoid sinus- Radiopaedia 3. Clinical-radiological aspects of primary extracranial meningioma of the ethmoid sinus in a child - Arq. Neuro-Psiquiatr. vol.66 no.2a São Paulo June 2008 4. Peter M. Som • Hugh D. Curtin- Head and Neck imaging
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!