The differential diagnosis of dural-based lesions Fig 1. in the brain varies from incidental and benign to symptomatic and malignant lesions. In our study the lesion ranges from grade I meningioma to rare primary dural based sarcoma and primary dural lymphoma.
Over the period from april 2017 to april 2019 we found that meningiomas are the most common primary dural lesions and was found in 189 patients.
Meningiomas are meningothelial cell neoplasms, which typically attach to the inner surface of the dura matter.
Most meningiomas are benign and categorized as WHO grade I.Fig 2.
Anaplastic meningioma Fig.3. has a clearly malignant cytology that resembles carcinoma or high-grade sarcoma, thus corresponding to WHO grade III.
The differential imaging feature of Grade II and grade III meningioma include general imaging features include indistinct tumor-brain interfaces, irregular tumor margins, inhomogeneous tumor appearances, and the lack of capsule-like enhancement at the tumor margins
Intracranial hemangiopericytomas are neoplasms of the pericytes that originate in the meninges, represent less than 1% of all CNS tumors(1), are aggressive they are typically encountered in younger adults.Bone erosion is a feature seen in more than half of hemangiopericytoma cases, are not associated with calcifications or hyperostosis, and they typically show heterogeneous enhancement Fig- 4.
Central nervous system (CNS) solitary fibrous tumors are rare, dural-based mesenchymal neoplasms. May erode bone if abutting the bone may show heterogeneous enhancement. Fig-5.
Plasmocytoma solitarily involving the CNS as dural-based lesions are rare. Plasmacytomas are extra-axial masses without calcification and shows typical punch out lytic lesion Fig-6.
Rosai-Dorfman disease is also known as sinus histiocytosis with massive lymphadenopathy. The disease commonly presents as massive, painless, bilateral lymph node enlargement in the neck with fever. Rosai-Dorfman disease in CNS usually presents as dural-based, epidural or subdural, contrast-enhancing masses that often elicit vasogenic edema in the underlying cerebral cortex and white matter. Fig- 7.
Neurosarcoidosis although it is very rare to have isolated neurosarcoidosis (i.e. without systemic disease), central nervous system symptoms are not uncommonly the first manifestation, and as such patients are often imaged without the diagnosis of systemic sarcoidosis having yet been made.Diagnosis is based on the documentation of systemic sarcoidosis in the absence of other neurological disease.A dural-based mass is one of the least common manifestations of neurosarcoidosis. Lesions may show homogeneous or heterogeneous enhancement. Variable amounts of vasogenic edema can also be seen in the white matter adjacent to the mass. Fig- 8.
CNS lymphoma leptomeningeal lymphoma accounts for two-thirds of cases of secondary CNS lymphomas, the remaining third presenting like primary CNS lymphomas. The frequency of secondary CNS lymphoma in patients with systemic lymphoma varies and is highly dependent on histologic subtype. The overall risk of CNS relapse in aggressive NHL is on the order of 2%–27%. Images show either homogeneous or inhomogeneous dense enhancement. Linear dural enhancement is usually seen on both sides of the dural mass (dural tail) and, although it is an extra-axial mass, white matter edema is usually present. Fig-9 secondary dural lymphoma Fig -10 primary dural lymphoma.
Dural metastases dural or pachymeningeal metastases are a relatively common cause of dural masses. Imaging shows heterogeneous dural based lesion with an enhancing dural tail mimicking a meningioma.
Melanoma metastases intracranial metastatic melanoma is the third most common brain metastasis.Melanoma metastases can be artificially divided into "melanotic" (containing greater than 10% melanotic cells on histopathology) or "amelanotic" (containing less than 10% melanotic cells). Typically shows T1 hyperintensity on mRI imaging with variable enhancement. Fig-11.
Primary dural sarcoma dural based sarcoma is a rare aggressive neoplasm arising from the multipotent primitive mesenchymal stem cells of the dura.Imaging findings are non specific and shows intense heterogeneous enhacement. Fig 12.