A special form of cerebral lacunae: expanding lacunae.

Abstract

The case of a 42 year old man with headache, blurred vision, and diplopia allowed the description of a particular form of cerebral lacunae-that is, expanding lacunae. Brain MRI showed hydrocephalus and multiple lesions in the thalamomesencephalic region. The radiological features of these lesions were similar to the histological brain coronal section of a case reported in 1983 in which expanding lacunae were related to a dilatation of the perivascular spaces and a focal segmental necrotising angiitis. The role of the lymphatic drainage of the brain is discussed to explain the dilatation of the perivascular spaces. The hypothesis of a hydrodynamic factor being responsible for the expanding character of the lacunae was suggested by the location of the lesions and the influence of various clinical events on the symptomatology.

Expanding lacunae causing triventricular hydrocephalus

“…Although MR imaging is suitable to differentiate the three fundamental types of brain lacunae, [5,8,11] a differential diagnosis that includes other intracranial cystic lesions in the same location, in particular those due to parasites (echinococcosis, cryptooccocosis, and cysticercosis), has to be considered. [10] Cryptococcus neoformans has a predilection for the brain perivascular spaces, [2,22] but cryptococcosis usually occurs against the background of acquired immunodeficiency syndrome and is associated with CSF abnormalities and extensive changes and contrast enhancement of adjacent brain parenchyma on imaging studies, which were absent in our patients. Lack of calcification and contrast enhancement is also unusual for cysticercosis, which has a predilection for the ventricular or subarachnoid spaces.…”

“…As well, no clinical correlate was found by Ogawa, et al, [17] in two cases of dilated perivascular spaces demonstrated by MR imaging in cerebral hemispheric white matter, although the results of a biopsy sample confirmed one of these cases. Also, in a 42-year-old man described by Homeyer, et al, [10] in whom a diagnosis of expanding lacunae based on MR imaging and negative laboratory examinations for parasites had been made, the expanding lacunae had a mesencephalothalamic distribution, causing stenosis of the aqueduct and triventricle hydrocephalus. The clinical features in that case included headache, blurred vision, diplopia, paresthesias to the upper limbs, skew deviation, and Parinaud's syndrome.…”

“…However, these cysts are not multiple as a rule, their content may not appear the same as CSF on MR imaging, and their location may not conform to the path of the penetrating arteries. [8,10,11,17] Proton MR spectroscopy is increasingly used as a supplement to MR imaging to characterize cystic lesions of the brain due to tumor, abscess, and parasitic infestations. [6,12] In parasitic cysts a wide range of abnormal metabolites, including alanine, acetate, succinate, and pyruvate, have been identified within cystic fluid in addition to a variable amount of lactate and the complete absence of normal brain metabolites.…”

“…Magnetic resonance (MR) imaging enables an in vivo demonstration of expanding lacunae and contributes to their differential diagnosis, which includes other brain cysts. [10,11,17] In the current report we describe two patients in whom mesencephalothalamic expanding lacunae were observed on MR imaging and in whom the referring complaints were related to triventricular hydrocephalus that was caused by obstruction and stenosis of the cerebral aqueduct and compression of adjacent brain parenchyma. …”

Spontaneous Regression and Recurrence of a Tumefactive Perivascular Space

“…Fibrosis and obstruction were thought to be the cause of dilatation of perivascular spaces in basal ganglia, based on light microscopy, scanning and transmission electron microscopy and direct visualization of etched paraffin blocks of post mortem specimens of brain by Pollock et al 3 . The other proposed mechanisms include disturbance of the drainage of interstitial fluid due to abnormal cerebrospinal fluid (CSF) circulation 8 , repeated mechanical trauma from CSF pulsations 12 , spiral elongation of ectatic penetrating blood vessels 13 , increased fluid exudation consequent to abnormal vascular permeability 14 and an ex vacuo effect secondary to ischemic perivascular tissue injury 15 . Although usually asymptomatic, giant perivascular spaces may be associated with non-specific symptoms.…”