Diffuse subependymal periventricular metastases. Report of three cases

Subependymal hyperintense layer on CISS sequence: An MRI study

PURPOSE

The present study aimed to explore the subependymal layers overlying the cerebral ventricles using magnetic resonance imaging.

METHODS

A total of 69 outpatients underwent constructive interference in steady-state (CISS) sequence in thin-sliced, coronal, and sagittal sections.

RESULTS

The subependymal layers were delineated as linear hyperintensities, coursing along the outer margins of the ventricular walls. On coronal images, the hyperintensities surrounding the anterior horn of the lateral ventricle were identified in 97% of patients, while those of the third ventricle were identified in 96% of patients. In the trigone and posterior horn of the lateral ventricle, the hyperintensities were delineated in all patients. On sagittal images, subependymal hyperintensities were identified in all. At the level of the anterior horn and third ventricle, the subependymal hyperintensities were found to communicate with the Virchow-Robin spaces (VRSs) in 68% and 65% of patients, respectively. At the level of the trigone and posterior horn of the lateral ventricle, the VRSs communicated with the subependymal hyperintensities in 83% of patients.

CONCLUSIONS

Subependymal hyperintensity may represent an inflow passage of the VRSs that jointly contribute to efficient transependymal migration of the interstitial fluid into the ventricular cerebrospinal fluid.

A Rare Case of Diffuse Subependymal Periventricular Metastases from Small Cell Lung Carcinoma

Small cell lung cancer, whose essence is neuroendocrine tumors, makes up proximately 14-20% of all lung cancer circumstances. Compared to non-small cell lung cancer, its clinical manifestation seems more positive and has a tendency to disseminate earlier in the process of its natural past. About 10% of patients present with brain metastases at the time of provisional diagnosis and sometimes all along the course of their disease, there will be 40-50% of developed brain metastases in addition. Although metastases in the brain parenchyma are often found in patients with advanced lung cancer, periventricular metastases are rare. We report one case of diffuse subependymal periventricular metastases from small cell carcinoma of the lung.

Endoscopy-verified occult subependymal dissemination of glioblastoma and brain metastasis undetected by MRI: prognostic significance

Although various prognostic indices exist for patients with malignant brain tumors, the prognostic significance of the subependymal spread of intracranial tumors is still a matter of debate. In this paper, we report the cases of two intraventricular lesions, a recurrent glioblastoma multiforme (GBM) and a brain metastasis, each successfully treated with a neuroendoscopic approach. Thanks to this minimally invasive approach, we achieved good therapeutic results: we obtained a histological diagnosis; we controlled intracranial hypertension by treating the associated hydrocephalus and, above all, compared with a microsurgical approach, we reduced the risks related to dissection and brain retraction. Moreover, in both cases, neuroendoscopy enabled us to identify an initial, precocious subependymal tumor spreading below the threshold of magnetic resonance imaging (MRI) detection. This finding, undetected in pre-operative MRI scans, was then evident during follow-up neuroimaging studies. In light of these data, a neuroendoscopic approach might play a leading role in better defining the prognosis and optimally tailored management protocols for GBM and brain metastasis.

Pigmented lesions of the central nervous system: radiologic-pathologic correlation

Pigmented lesions of the central nervous system (CNS) are a diverse group of entities that run the gamut from benign to malignant. These lesions may be well circumscribed or diffuse, and their imaging appearances are influenced by the degree of melanin content as well as the presence or absence of hemorrhage. Pigmented lesions include primary melanocytic lesions of the CNS and metastatic melanoma, as well as other CNS neoplasms that may undergo melanization, including schwannoma, medulloblastoma, and some gliomas. Primary melanocytic lesions of the CNS arise from melanocytes located within the leptomeninges, and this group includes diffuse melanocytosis and meningeal melanomatosis (seen in neurocutaneous melanosis), melanocytoma, and malignant melanoma. Primary melanin-containing lesions of the CNS must be differentiated from metastatic melanoma because these lesions require different patient workup and therapy. Absence of a known primary malignant melanoma helps in the differential diagnosis, but an occult primary lesion outside the CNS must be sought and excluded. Pigmented lesions of the CNS are uncommon, and knowledge of their imaging characteristics and pathologic features is essential for their identification.

A variety of appearances of malignant melanoma in the head: a review

Imaging is frequently requested to evaluate patients with malignant melanoma for metastases. When melanoma metastasizes to the head, the lesions can have a variety of appearances and can occur in a variety of locations. The usual appearances of malignant melanoma on magnetic resonance images include the melanotic and amelanotic patterns. The melanotic pattern consists of high signal intensity on T1-weighted images and low signal intensity on T2-weighted images. In the amelanotic pattern, the lesion is hypointense or isointense to the cortex on T1-weighted images and hyperintense or isointense to the cortex on T2-weighted images. However, there is frequent deviation from these patterns. Other patterns include small and rapidly growing metastases, miliary metastases, and subependymal metastases. Although the brain is the most common site of metastases to the head from melanoma, melanoma can metastasize to almost any intracranial or extracranial structure. Structures in the head that can be involved by metastases from melanoma include bone, muscle, the nasopharynx and mucosa, the parotid gland, the meninges, the choroid plexus, the internal auditory canal, and the orbit. The radiologist needs to be aware of these varied appearances and the relatively ubiquitous sites of involvement to better detect these lesions.

Periventricular enhancement: a non-pathognomonic sign of intracerebral tumours

Four cases of periventricular contrast enhancement on computed tomography due to different tumours are reported, emphasizing that periventricular contrast enhancement is a non-specific radiological sign.