Intracranial and spinal epidermoids are benign slow-growing congenital lesions. They are predominantly intradural, extra-axial in location, with intraaxial locations (intra-parenchymal and spinal intramedullary) being rare. The most common locations of intradural epidermoids are cerebellopontine angle cistern followed by supra-and para-sellar regions, and fourth ventricle. Less common locations include inter-hemispheric fissure, sylvian fissure, lateral ventricle, intracerebral, velum interpositum cistern, superior cerebellar cistern and pineal gland. They can also be extradural, usually arising in the diploic space of the calvaria, though they are less common. Magnetic resonance imaging is the primary modality for diagnosis and knowing the extent of the lesion. In this pictorial review, we intend to illustrate their classical and unusual locations, atypical imaging findings including calcifications, rare complications like haemorrhage or spontaneous rupture.
Neurovascular conflicts are common in the posterior fossa and basal cisterns due to coexistence of important neural and vascular structures. Neurovascular conflict arising from compression of the cranial nerves by pulsatile flow in the adjacent atherosclerotic arteries is well known and is associated with conditions like trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia. The medulla is known to be affected by dilated tortuous (dolichoectatic) vertebrobasilar arteries in the elderly or hypertensive. The vertebral artery causing the compression can be dolichoectatic or normal dominant vertebral artery or an elongated tortuous artery. Very few cases of medullary compression by non-dolichoectatic elongated tortuous or dominant vertebral artery were reported in the literature. In this article, we report three cases of medullary compression by the dominant and angulated vertebral artery. Magnetic resonance (MR) imaging with MR angiography showed indentation of the anterolateral aspect of the inferior medulla by the vertebral artery. The patients are managed conservatively and on regular follow-up.
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