Case Reports ABC Fax + 41 61 306 12 34 E-Mail karger@karger.ch www.karger.com © 2003 S. Karger AG, Basel Accessible online at: www.karger.com/ced Cerebrovasc Dis 2003;16:174–176 DOI: 10.1159/000070599 Traumatic Intracystic Hemorrhage in a Case with Thalamo-Mesencephalic ‘Expanding Lacunae’: An Uncommon Cause of Sudden-Onset Neurological Signs Jessica Mandrioli a , Patrizia Sola a , Raffaele Lodi b , Stefano Vallone a , Bruno Barbiroli b , Pietro Cortelli a a Department of Neuroscience, University of Modena, Modena, and b Department of Clinical Medicine and Biotechnology ‘D. Campanacci’, University of Bologna, Bologna, Italy Introduction Brain intraparenchymal multicystic lesions of the brainstem and basal ganglia are rare and the observation of ‘expanding lacunae’ (EL) is exceptional: only 8 cases have been described [1–7]. They are intraparenchymal multilobulated cavities of variable diameter filled with cerebrospinal fluid (CSF) and are mostly localized in the thala- mo-mesencephalic region. The etiology and pathogenesis is unclear. All cases reported share three common features: (1) intraencephalic multilobulated cavities called cysts or lacunae; (2) typical mesence- phalo-thalamic topography of the thalamo-mesencephalic arterial pedicle, and (3) a progressive hydrocephalic syndrome. We describe a patient with mesencephalo-thalamic EL who developed sudden-onset neurological signs after mild cranial trauma associated with bleeding in the most caudal cyst. Case Report A 51-year-old woman was admitted to our hospital on September 26, 2001, for right facio-brachial hypoesthesia and paraesthesia which had occurred a few minutes after a mild head trauma due to a syncopal episode while she was getting up when she was affected by a flu-like syndrome. Her past history was irrelevant, except for a postu- ral right hand tremor that had appeared at the age of 47 years and had progressively impaired her quality of life, especially writing. A poly- graphic study showed a postural right hand tremor with a 5-Hz fre- quency and an alternating pattern of agonist and antagonist contrac- tion. Familiarity for essential tremor was absent but propranolol (80 mg/day) was started and showed significant clinical benefit. Brain CT was also recommended and disclosed multilobulated cystic lesions. MRI showed well-demarcated multiple cysts, with a maxi- mum transverse diameter of 40 mm, localized in the thalamo-pedun- cular region with a partial involvement of the left internal capsule (fig. 1a). The cysts had a bunch-of-grapes aspect with a CSF-like fluid signal intensity without gadolinium enhancement of the cyst walls. The cyst compressed the left posterior mesencephalon and deformed the third ventricle and left lateral ventricle. The apparent diffusion coefficient of water (ADC), measured using diffusion- eighted MRI (DWI; fig. 1b) was similar in the cystic cavities (mean B SD: 3.18 B 0.16 ! 10 –3 mm 2 /s, 6 different regions of interest) and in the lateral ventricles (3.19 B 0.09 ! 10 –3 mm 2 /s, 6 different regions of interest, p = 0.8). These quantitative findings confirmed that the cysts contained normal CSF. No ADC changes were detected in the surrounding brain parenchyma. On admission, history taken excluded vascular risk factors such as hypertension, hyperlipidemia, smoking, or diabetes. Neurological examination revealed right-sided pin-prick, tactile and proprioceptive hypoesthesia, right central facial nerve palsy and mild left upper limb weakness. Routine laboratory values were normal. Neuroimaging did not show changes in the shape or size of the EL, but the cyst near the left cerebral peduncle was hyperdense on CT scans and hyperintense in T 1 and prolonged TR sequences (fig. 2a). Compression of the adjacent parenchyma was similar to the previous MR, with no evidence of edema. After two weeks the patient was discharged with a mild improvement of senso- ry and motor neurological signs. Follow-up MRI in December 2001 showed multicystic lesions unchanged in size without intralacunar bleeding (fig. 2b) Discussion Three types of brain lacunae have been described on the bases of brain CT, MRI and histopathological studies [8]. Type III lacunae are related to dilatation of perivascular spaces secondary to small vessel damage due to arteriolar occlusion or loss of autoregulation [8]. They are round, regular cavities, marked by a single layer of epi- thelial cells and contain a patent artery with normal walls. A peculiar feature of type III lacunae is that they can expand, becoming giant (‘expanding lacunae’) and causing hydrocephalus by compressing the ventricles or the aqueduct. Neuropathological examination [1] disclosed intracerebral multi- ple cavities of variable diameter, located in the territory of the para- median mesencephalo-thalamic artery with a well-marked wall, and a histologically normal artery crossed the cavity which was otherwise empty. EL behave like space-occupying lesions compressing the adja- cent brain parenchyma, which shows mild gliosis, pericallosal demy- elination and dilated perivascular spaces. Brain arteries did not show histological alterations but there was severe segmental necrotizing angeitis of the left superior paramedian mesencephalic artery, with- out occlusion in its extra- and intramesencephalic tract. The physiopathology of EL is still unknown. The following hypotheses have been proposed to explain the origin of the abnormal- ly dilated perivascular spaces: (1) impaired artery wall permeability secondary to vasculitis [1] or to an anomalous vascular nest [6]; (2) impaired interstitial fluid drainage secondary to obstruction of lymphatic drainage of the brain [5], and (3) impaired brain intersti- tial fluid drainage due to increased pressure of intraventricular CSF, which would also explain the frequency of hydrocephalus. The fluc- tuating clinical picture, the deterioration after head injury, the improvement after shunting and the lumbar puncture support the role of a hydrodynamic factor [9]. Lastly, a mechanical etiology has been suggested, consisting of ventricular wall rupture allowing CSF to flow into the nearby brain parenchyma, similar to the CSF expan- sion into the spinal cord to form a syrinx [3]. In our patients, the diagnosis of mesencephalo-thalamic EL was based on CT and MR [10] imaging findings and a slowly progressive postural hand tremor. The exclusion of cystic lesions other than EL