Fourth ventricle lymphoma
Neurosurgery Department, University General Hospital of Alicante, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), Alicante, Spain
A primary central nervous system lymphoma should be listed in the differential diagnosis of fourth ventricle tumors with well-circumscribed margins and homogenous contrast enhancement. 1).
A primary central nervous system lymphoma (PCNSL) frequency map showed that these tumors tended to occur around the lateral, third and fourth ventricles. Moreover, subtypes were classified as germinal center B (GCB) (27 cases) and non-GCB (63 cases) PCNSL frequency maps showed GCB lymphomas located at the upper tegmentum and cerebellum around the fourth ventricle, while non-GCB lymphomas tended to occupy the anterior fornix. These differences were significant and confirmed by the existence of voxels with P values <.05 (random permutation analysis with voxel-wise Fisher’ exact test). This is the very first report to address phenotypical and spatial distributional differences between GCB and non-GCB PCNSL using an MR group analytical method 2).
Primary central nervous lymphoma (PCNSL) is an important consideration in the differential diagnosis of intracranial mass lesion. The unusual location in surgically accessible fourth ventricle in posterior fossa, the isolation of the tumor may present a compelling indication for surgical resection.
Hsu et al. suggest that primary lymphoma should be considered with homogenous lesions of the 4th ventricle. Also aggressive surgical resection in this surgically accessible location, instead of biopsy only, is rational. 4).
A 66-year-old man with 2-month history of dizziness and 1-month history of diplopia. Cranial magnetic resonance imaging (MRI) disclosed two solid masses, one in the right lateral ventricle and another in the fourth ventricle. A surgical biopsy was performed on the basis of safety. The diagnosis of large B-cell lymphoma was made postoperatively. The patient recovered without additional deficits and was then commenced on chemotherapy and remained well 6 months after the diagnosis. It is an extremely rare case of primary central nervous system lymphoma with multifocal ventricular involvement. 5)
A 65-year-old man presented with a two-week history of weight loss, headaches, blurred vision, asthenia and quickly worsening walking impairment. He denied photophobia, neck stiffness, fever, nausea or vomiting.Neurological examination showed global motor slowing, tendency to fall asleep during the clinical examination, generalized weakness against resistance to head and limbs, and osteotendon reflexes present in the upper limbs, but not evoked in the lower limbs. No sensitive deficit or focal neurologic sign was recognizable.Non-contrast multislice computed tomography (MSCT) of the head was performed in the emergency department, showing diffuse periventricular white matter and thalamic mild hyperdensity.Lumbar puncture, blood tests, including serology for HIV and other infections, were negative.On the third day the patient, showing decreased consciousness, underwent magnetic resonance imaging (MRI) with contrast medium injection. MRI revealed the presence of multiple pseudonodular avidly enhancing lesions, supra and infratentorial, crossing the midline, involving the ventricular system, including the fourth ventricle, with extension into the surrounding white matter, the corpus callosum, the thalamus and the hypothamalus.A stereotactic biopsy led to a diagnosis of diffuse large B-cell lymphoma, primarily located in the central nervous system (PCNSL).After the completion of the first phase of treatment (immunotherapy with intravenous Rituximab and corticosteroid), the MRI showed a marked regression of tumor masses 6).
Grossman et al. report a case of primary CNS lymphoma located in the floor of the fourth ventricle that showed intense fluorescence after preoperative administration of 5 aminolevulinic acid. The authors believe that this is the first demonstration of a 5 aminolevulinic acid fluorescence guided resection in primary CNS lymphoma 8).
A 77-year-old man had a 1 week history of intermittent vertigo, nausea, vomiting, and progressively unsteady gait. CT scans of the brain showed a fourth ventricle tumor. MRI revealed a 2.5 cm dumbbell-shaped avidly-enhancing tumor in the fourth ventricle. Metastasis or high-grade glioma was suspected. The neuropathological findings were compatible with a diffuse large B-cell lymphoma. A slit lamp examination, bone marrow biopsy, and imaging studies for extracranial lesions were unremarkable 9).
Primary fourth ventricular B-cell lymphoma in an immunocompetent patient 10)
A 50-year-old male who developed signs and symptoms of increased intracranial pressure. Imaging revealed the presence of a fourth ventricle mass with obstructive hydrocephalus. First, the patient underwent emergency endoscopic third ventriculostomy followed, few days later, by complete tumor resection via a posterior fossa craniotomy. Postoperative histopathology revealed the lesion to be a PCNSL. He received adjuvant chemotherapy and radiation and remained with no recurrence on regular imaging studies for 18-month followup 12).
A 51-year-old woman presented with a 2-month history of double vision and numbness around her left ear. She subsequently became unsteady on her feet and developed further cranial nerve abnormalities, before complaining of headache, nausea and vomiting. Imaging revealed features suggestive of two intracranial lesions; one non-contrast-enhancing high-signal area in the cerebellum with associated calcification, and a second contrast-enhancing low-signal area in association with the fourth ventricle, and at surgery there were two apparent components to the tumor. The histopathological features were those of a low-grade, focally calcified tumor comprising atypical ganglion and glial cells with interspersed Rosenthal fibres. Mitotic figures were not seen, and there was no necrosis. An infiltrate of small reactive lymphocytes was interspersed among the neoplastic cells. Immunohistochemistry revealed expression of synaptophysin by many of the dysplastic ganglion cells, with some co-expressing neurofilament protein and occasionally glial fibrillary acidic protein (GFAP). Several of the dysplastic ganglion cells also expressed CD34. The glial cell population was highlighted by GFAP. Ki-67 (MIB-1) activity was not noted among the neoplastic populations–the few positive nuclei in these areas were those of interspersed reactive CD3-positive T lymphocytes. In addition, at the edge of one of the biopsies was a dense infiltrate of mitotically-active large atypical CD 20-positive B lymphocytes, among which the Ki-67 (MIB-1) labeling index reached 80%. The final diagnosis was diffuse large B cell lymphoma arising within a ganglioglioma of the cerebellum, and this is believed to be the first reported case 16).