Solitary primary leptomeningeal glioma: case report

Primary and secondary leptomeningeal gliomatosis in dogs

Leptomeningeal gliomatosis (LG) is characterized by extensive dissemination of neoplastic glial cells in the subarachnoid space either without an intraparenchymal glioma (primary LG or PLG) or secondary to an intraparenchymal glioma (secondary LG or SLG). Given the low frequency of LG in human and veterinary medicine, specific diagnostic criteria are lacking. Here, we describe 14 cases of canine LG that were retrospectively identified from 6 academic institutions. The mean age of affected dogs was 7.3 years and over 90% of patients were brachycephalic. Clinical signs were variable and progressive. Relevant magnetic resonance image findings in 7/14 dogs included meningeal enhancement of affected areas and/or intraparenchymal masses. All affected dogs were euthanized because of the poor prognosis. Gross changes were reported in 12/14 cases and consisted mainly of gelatinous leptomeningeal thickening in the brain (6/12 cases) or spinal cord (2/12 cases) and 1 or multiple, gelatinous, gray to red intraparenchymal masses in the brain (6/12 cases). Histologically, all leptomeningeal neoplasms and intraparenchymal gliomas were morphologically consistent with oligodendrogliomas. Widespread nuclear immunolabeling for OLIG2 was observed in all neoplasms. The absence of an intraparenchymal glioma was consistent with PLG in 3 cases. The remaining 11 cases were diagnosed as SLG.

[Primary leptomeningeal gliomatosis treated with temozolomide: a case report]

A 35-year-old man was admitted to our department for loss of consciousness. CT and MRI revealed diffuse enhancement of the subarachnoid space surrounding the brainstem and the cerebellar sulci, without any parenchymal lesions in the brain or the spinal cord. Furthermore, gadolinium-enhanced MRI revealed a nodular lesion with heterogeneous enhancement in the right prepontine cistern, at the site from which a biopsy was obtained via right lateral suboccipital craniotomy on the day following admission. Histopathological examination of the resected specimen revealed glioblastoma multiforme. Based on the radiological and histopathological findings, the patient was diagnosed with primary leptomeningeal gliomatosis (PLG). The patient received temozolomide chemotherapy with concurrent radiotherapy and showed radiological remission, 12 months after diagnosis. However, he developed local recurrence 6 months later and died 23 months after diagnosis. Autopsy findings showed tumor cell infiltration of the leptomeninges, as well as the brain and spinal parenchyma. PLG should be considered in the differential diagnosis in patients with diffuse leptomeningeal enhancement even without parenchymal lesions on radiological imaging. A surgical biopsy is recommended for prompt and accurate diagnosis in such cases.

Solitary Extra-axial Intracranial Primary Meningeal Pleomorphic Xanthoastrocytoma: An Extremely Rare Case

BACKGROUND

Pleomorphic xanthoastrocytomas (PXAs) are a rare type of astrocytoma, which, similar to other gliomas, can rarely arise from glial nests in the meninges, manifesting as an extra-axial mass. We describe a solitary extra-axial intracranial primary meningeal PXA in the pediatric age group, which was masquerading as a tentorial meningioma.

CASE DESCRIPTION

A 9-year-old girl presented with features of raised intracranial pressure. Imaging revealed a dural-based mass in the tentorial region suggestive of a meningioma. This suspicion was further strengthened by intraoperative visualization of an extra-axial tumor with wide tentorial attachment. Near-total excision was achieved. Histopathologic examination established the diagnosis of PXA. Given the tumor's apparent meningeal origin and lack of connection with brain parenchyma in imaging and intraoperative findings, primary meningeal PXA was diagnosed. The absence of coexisting tumor foci on spinal magnetic resonance imaging further refined the diagnosis as solitary extra-axial intracranial primary meningeal PXA. The patient received radiotherapy for the residual tumor and was doing well at 6 months after presentation; however, she was lost to follow-up after that.

CONCLUSIONS

Solitary extra-axial intracranial primary meningeal PXA is an extremely rare entity with only 3 reported cases in the literature including the present case. This is the first report of such a tumor in a pediatric patient. This report also highlights that primary meningeal PXA can manifest as an extra-axial mass lesion and may warrant inclusion in the differential diagnosis of extra-axial mass lesions.

Primary Focal Intracranial Leptomeningeal Glioma: Case Report and Review of the Literature

BACKGROUND

Primary focal intracranial leptomeningeal glioma (PFILG) is considered a rare solitary glial tumor arising from the leptomeninges without brain attachment or evidence of primary neoplasm elsewhere within the neuraxis. We report a case of PFILG in a left parietal location and provide a concise review on its clinicoradiologic, histopathologic, and management characteristics.

CASE PRESENTATION

A 75-year-old woman presented with focal motor seizures involving the right upper limb with associated occasional headache. Magnetic resonance imaging (MRI) of the brain revealed a small focal lesion attached to the left parietal dura with underlying brain parenchymal signal changes, and contrast-enhanced images showed heterogeneous enhancement of the tumor and meninges. The repeated MRI brain images within a month of primary imaging revealed significant progression of the size of lesion along with invasion of underlying parietal lobe parenchyma. The patient underwent gross total resection of the lesion, and the histopathologic diagnosis was glioblastoma multiforme (GBM), World Health Organization grade 4, isocitrate dehydrogenase wild type. The patient recovered well from surgery without deficits; however, she refused adjuvant treatment. MRI of the brain repeated 3 months after surgery revealed significant progression of the GBM with mass effect. Although adjuvant treatment was then started, she could not tolerate it and died 4 months after surgery.

CONCLUSION

The possibility of high-grade PFILG should be considered in any aggressive extra-axial focal lesion. The definitive diagnosis can be made after histologic examination. Although surgery followed by adjuvant treatment is considered the mainstay of treatment, the overall prognostic outcome of high-grade PFILG is dismal.

Solitary primary intracranial leptomeningeal glioblastoma invading the normal cortex: Case report

Solitary primary intracranial leptomeningeal glioma (PLG) is a rare entity of glioma. PLG arises from the heterotopic glial tissue in the subarachnoid space and usually grows there without parenchymal invasion. The present study reported a case of solitary PLG, pathologically diagnosed as glioblastoma, that invaded the temporal cortex and finally disseminated to the spinal cord. A 55-year-old woman had headaches and visited Nihon University, Itabashi Hospital. Head magnetic resonance imaging showed a solid mass mainly located in the right middle fossa extending to the frontal base with strong enhancement effect after contrast medium injection. A conventional angiogram showed a tumor arising from the middle meningeal artery. Fronto-temporal craniotomy was performed to remove the tumor. During reflection of the dura matter, there were numerous small vessels connecting the dura matter and the cortical surface. The tumor was located in the Sylvian fissure and extended around the middle cerebral artery. The border between the tumor and the normal temporal lobe was unclear. Temporal lobectomy was done, but the tumor was left around the perforators of the middle cerebral artery. Hematoxylin and eosin staining showed typical glioblastoma with high cellularity, mitosis, pseudopallisading and vascular proliferation. The tumor cells were immunohistochemically negative for isocitrate dehydrogenase (IDH)1-R132H indicating glioblastoma, IDH-wild type. The patient received chemotherapy and radiation therapy, and was discharged from the hospital. Six months later, local regrowth and spinal dissemination were found. Despite additional chemotherapy and radiation therapy, the tumor became uncontrollable and the patient succumbed. Only 15 cases of solitary PLGs have been reported previously. The IDH status of these tumors have not been investigated in most cases; however, pathological grading varies from lower to higher grade glioma. Together with the pathological difference of astrocytic or oligodendrocytic tumors, solitary PLGs may develop due to various gene alterations similar to intra-axial gliomas.

Primary Meningeal Pleomorphic Xanthoastrocytoma With Anaplastic Features: A Report of 2 Cases, One With BRAF(V600E) Mutation and Clinical Response to the BRAF Inhibitor Dabrafenib

Primary meningeal gliomas are rare tumors composed of a heterogeneous group of neoplasms. We present 2 clinically aggressive cases of primary meningeal pleomorphic xanthoastrocytoma that clinically mimicked meningioma. One case presented in the posterior fossa of a 56-year-old woman; the other centered on the left operculum of a 35-year-old woman. These cases showed many of the classic features of pleomorphic xanthoastrocytoma, except that xanthomatous cells were rare and eosinophilic granular bodies were inconspicuous. Both cases exhibited high proliferative indices and superficially invaded the brain. One case harboring a BRAF mutation disseminated to the thecal sac and showed a clinical response to the targeted BRAF inhibitor dabrafenib. These cases seem to represent an unusual primarily extra-axial presentation of pleomorphic xanthoastrocytoma and may account for at least some of the previously reported cases of primary meningeal glioma and/or glial fibrillary acidic protein-immunoreactive meningioma variants. We suggest that BRAF mutation analysis be considered in all meningeal lesions showing atypical histologic or immunohistochemical profiles, particularly those exhibiting glial differentiation, as a diagnostic aid and possible indication for targeted therapy.

Primary diffuse leptomeningeal gliosarcomatosis

Primary diffuse leptomeningeal gliomatosis (PDLG) is a rare condition with a fatal outcome, characterized by diffuse infiltration of the leptomeninges by neoplastic glial cells without evidence of primary tumor in the brain or spinal cord parenchyma. In particular, PDLG histologically diagnosed as gliosarcoma is extremely rare, with only 2 cases reported to date. We report a case of primary diffuse leptomeningeal gliosarcomatosis. A 68-year-old man presented with fever, chilling, headache, and a brief episode of mental deterioration. Initial T1-weighted post-contrast brain magnetic resonance imaging (MRI) showed diffuse leptomeningeal enhancement without a definite intraparenchymal lesion. Based on clinical and imaging findings, antiviral treatment was initiated. Despite the treatment, the patient's neurologic symptoms and mental status progressively deteriorated and follow-up MRI showed rapid progression of the disease. A meningeal biopsy revealed gliosarcoma and was conclusive for the diagnosis of primary diffuse leptomeningeal gliosarcomatosis. We suggest the inclusion of PDLG in the potential differential diagnosis of patients who present with nonspecific neurologic symptoms in the presence of leptomeningeal involvement on MRI.