Spectrum of benign intracranial cystic lesions

Transcription

1 Spectrum of benign intracranial cystic lesions Poster No.: C-1945 Congress: ECR 2012 Type: Educational Exhibit Authors: B. Alami, A. L. M. Youssef, O. Addou, M. Jaffal, N. Sqali, M. Boubou, M. Mustapha, T. Siham ; Fes/MA Keywords: Cysts, Imaging sequences, MR-Diffusion/Perfusion, MR, CT, Neuroradiology brain DOI: /ecr2012/C-1945 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 40

2 Learning objectives 1- A broad spectrum of diseases can cause intracranial cysts. The discussion includes an algorithm that describes respectively: primary non-tumoral intracranial cysts; inflammatory pseudo-cyst, and infectious pseudo-cysts. 2- The second purpose of our study was to show the imaging findings of cystic intracranial lesions and to recognize their differential diagnosis. Page 2 of 40

3 Background We report a retrospective study that evaluates 66 cases of cystic intracranial lesions or with cystic components, seen during the two-year period from January 2009 to February Our patients underwent cerebral CT scanning (n=26) and/or undergo cerebral MR imaging (n=50) (diagram.1). Diagnosis of intracranial cyst were confirmed by imaging findings and if necessary with histopathological analysis. Page 3 of 40

4 Images for this section: Fig. 24: Diagram.1 Page 4 of 40

5 Imaging findings OR Procedure details Imaging Findings: The results that were obtained (Diagram.2): Arachnoid cysts (n=17), porencephalic cysts (n=9), enlarged perivascular spaces or Virchow-Robin spaces (n=9), pineal cyst (n=1), Rathke'cleft cyst (n=3), neuroglial cyst (n=1), intracranial dermoid cyst (n=1), epidermal cysts (n=4), pseudo-inflammatory cyst associated to multiple sclerosis (n=1), hydatid cysts (n=8), neurocysticercosis cysts (n=2), tuberculosis abscess (n=3), pyogenic abcess (n=5), toxoplasmosis (n=1), and amoebic brain abscess (n=1). 1- Arachnoid Cyst : Definition: Arachnoid cysts are benign, congenital, intra-arachnoidal spaceoccupying lesions that are filled with clear CSF; They do not communicate with the ventricular system. 1% of all intracranial masses, Clinical presentation: o Often asymptomatic, found incidentally, o Headache, o Dizziness, o Hearing loss, o Rarely obstructive hydrocephalus. Imaging: o Location: 50-60% middle cranial fossa (Fig.1). 10% cerebellopontine angle (Fig.2), 10% suprasellar. o Isointense to CSF, o Typically suppress completely on FLAIR images. o No restriction on diffusion-weighted images. Differential Diagnosis: o Epidermoid cyst, o Chronic subdural hematoma, o Porencephalic cyst, o Subdural hygroma, o Neurenteric cyst. Page 5 of 40

6 2- Enlarged perivascular spaces (PVSs): The PVSs of the brain are normal structures lined by pia that accompany arteries and arterioles as they penetrate the brain, and they are filled with CSF. Enlarged perivascular spaces are common incidental "leave me alone" lesions. Imaging : o Prominent PVSs are considered a normal variant. o Location: Often occur in clusters in the basal ganglia (Fig.3) or midbrain. o They are as small as 1 mm in diameter with a round, oval, or curvilinear shape. o Isointense to CSF at all sequences, including FLAIR. o No contrast enhancement. o No diffusion restriction. o Giant tumefactive PVSs are most common in the mesencephalothalamic region and may have associated obstructive hydrocephalus. Differential Diagnosis: o Lacunar infarcts, o Cystic neoplasms, o Parasitic cysts, o Ventricular diverticula, o Cystic infarction, o Neuroepithelial cysts. 3- Porencephalic cyst: Porencephalic cysts are congenital or acquired cavities within the brain parenchyma (traumatic, ischemic or post-surgical); they communicate with the subarachnoid space or the ventricular system. Imaging (Fig.4): o Variable size. o Enlargement of the ventricular system and sulci adjacent. o Adjacent brain atrophy. o The same appearance as CSF at all MR sequences. o Adjacent white matter typically shows hyperintensity on T2-weighted and FLAIR images (Gliosis). Differential Diagnosis Page 6 of 40

7 o Arachnoid cyst, o Schizencephaly, o Ependymal cyst, o Encephalomalacia, o Hydranencephaly. 4- Neuroglial cyst: Neuroglial cysts are benign epithelial-lined lesions that occur anywhere in the neuraxis. They are uncommon, representing fewer than 1% of intracranial cysts. Imaging (Fig.5): o Location: the frontal lobe is the most typical location, o Variable size. o Smooth, rounded borders cysts, o Intraparenchymal neuroglial cysts are more common than extraparenchymal cysts, o Contain clear fluid that resembles CSF, o No enhancing. Differential Diagnosis o Enlarged PVS, o Infectious cyst, o Porencephalic cyst, o Arachnoid cyst. 5- pineal cyst: Nonneoplastic intrapineal glial-lined cyst. Clinically silent, discovered incidentally. Large cysts (> 1 cm) may become symptomatic. Imaging (Fig.6): o Location: Above tectum, below internal cerebral veins. o Size: Most are small (<1 cm), may be up to 2 cm or more. Page 7 of 40

8 o Best diagnostic clue: Homogeneous fluid-filled mass above, clearly distinct from tectum. o T1WI: 55-60% slightly hyperintense to CSF. o FLAIR: Doesn't suppress (moderately hyperintense). o 60% rim or nodular enhancement. Differential diagnosis: o Pineal gland normal (can be cystic), o Pineocytoma, o Epidermoid cyst, o Arachnoid cyst. 6- Rathke cleft cyst: Non-neoplastic cyst arising from remnants of squamous epithelium of Rathke's cleft. Imaging (Fig.7): o Nonenhancing noncalcified intra- and/or suprasellar cyst with an intracystic nodule. o T1 WI: 50% Hyperintense 50% hypointense. o T2 WI: 70% Hyperintense 30% hypointense. o Intracystic nodule hyper T1, hypot2, non-enhanced Neurenteric cysts (NCs): NCs are rare benign malformative endodermal CNS cyst (Persistent neurenteric canal). Imaging: o Ovoid/lobulated mass, small, < 2 cm. o Location: Posterior fossa: prepontine cistern +++ (Fig.8). Craniovertebral junction +++. Supra tentorial NCs are rare. Signal intensity vary depending upon protein content of the cyst fluid: Page 8 of 40

9 o The most are proteinaceous. o T1 WI: isointense to slightly hyperintense (compared with CSF). o T2WI: hyperintense. o FLAIR: hyperintense. o Diffusion: may show mild restriction. Differential Diagnosis: o Epidermoid cyst, o Arachnoid cyst, o Endodermal cysts (Rathke and colloid). 8- Epidermoid cyst (EC): EC is a congenital lesion resulting from inclusion of ectodermal elements during neural tube closure. Rare primary intracranial tumors (0.2%-1.8%). Age: years, peak incidence at 40 years. Clinical presentation: o Headaches +++; o Cranial nerve deficits ; o Cerebellar symptoms ; o Seizures ; o Raised intracranial presure. Imaging : o Location: Cerebellopontine angle cistern (40%-50%); Fourth ventricle (17%); Sellar and/or parasellar (10%-15%). Less frequent Seats: cerebral hemispheres, brainstem. o CT : Lobulated lesion that fills and expands CSF spaces and exerts gradual mass effect, insinuating between vessels and nerves. Resembles CSF. Page 9 of 40

10 Enhancement of the wall: rare. Calcification (25%). Hyperdense ECs are rare (Haemorrhage, saponification, or high protein content). o MR (Fig.9,10): Usually iso intense to CSF on T1 and T2 images. Rarely they can be high on T1 and are known as white epidermoids. Thin enhancement around the periphery may sometimes be seen. Rare intralesional haemorrhage can give intrinsic high signal. FLAIR: Usually doesn't completely null. DWI: restrict (show high signal intensity) +++. DW imaging could successfully differentiate epidermoid tumors. Differential Diagnosis: o Arachnoid cyst+++; o Neurocysticercosis; o Dermoid cyst ; o Cystic neoplasm. 9- Dermoid cysts: Extremely rare congenital ectodermal inclusion. Clinical presentation: o Uncomplicated dermoid: Headache (32%), seizure (30%). o Rupture can cause significant morbidity/mortality. Imaging (Fig.11): o Usually located in the midline (suprasellar +++). o Unruptured cysts have the same imaging characteristic as fat: All are hyperintense on T1-WI and do not enhance. o The masses have heterogeneous signal intensity on T2- WI and vary from hypo- to hyperintense. This explains the interest of MRI sequences with fat suppression signal to confirm the diagnosis. Page 10 of 40

11 o Ruptured cyst: fat droplets in the subarachnoid cisterns, sulci, and ventricles. o Risk: break with chemical meningitis, malignant transformation in carcinoma. Differential Diagnosis o Epidermoid; o Craniopharyngioma; o Teratoma; o Lipoma. 10- Pseudotumor cystic demyelinating Plaque: Multiple Sclerosis (MS) is an inflammatory demyelinating disease of central nervous system. The clinical form of pseudo-tumor is often acute with severe deficit. The tumor-like form of MS is characterized by the presence of extensive demyelinating lesion greater than 2 cm in diameter simulating a tumor. 3 Pathological forms have been isolated: o Marburg: One or more large lesions, Inconsistently and partially enhanced by the Gadollinium +++. o Schilder (Fig.12): Rather affects children; One or more roughly symmetrical lesions located in centrum semiovale and measuring at least 2 to 3 cm; Histopathology: similar to that present in the MS. o Balo's concentric sclerosis: Lesion composed by an alternation concentric bands of normal myelin "bulb onion" shape Signs in favor of extensive demyelinating lesions: Page 11 of 40

12 The clinical context; The association with other demyelinating lesions ; Small mass effect relative to size of the lesion. An incomplete ring enhancement ==> horseshoe open to the gray matter +++. Differential Diagnosis: Glioma low or high grade; Lymphoma; Metastatic neoplasm; Brain abscess or ischemic stroke. 11- Neurocysticercosis: Neurocysticercosis is a common neurologic dis order caused by the encysted larva of the tape worm Taenia solium. Four pathologic stages: Vesicular, colloidal, vesicular, granular nodular, and nodular calcified. Clinical presentation: o Seizure, headaches, o The most common cause of acquired epilepsy worldwilde. Imaging (Fig.13): o Best diagnostic clue: Cyst with "dot" inside. o Location: Subarachnoid-cisternal+++; Parenchymal (near the gray matter-white matter junction +++); Intraventricular; Spinal forms: rare. Imaging varies with development stage (Table 1). Differential Diagnosis: Page 12 of 40

13 o Abscess; o Tuberculosis; o Neoplasm (primary or metastatic); o Arachnoid cyst; o enlarged PVSs, o Other parasitic infections. 12- Hydatid Cyst: Intracranial hydatid cysts are parasitic infections caused by the larval stage of Echinococcus granulosus. Usually occurs in children. Imaging (Figs.14,15,16): o Usualy single and unilocular. o Multilocular or multiple: rare. o Location: Cerebral hemispheres particularly the territory of middle cerebral artery +++. Subarachnoid spaces. o CT appearance: Spherical cystic lesion with sharply defined border and attenuation similar to that of CSF. o MRI: Well-defined rounded cystic lesion with attenuation or signal intensities similar to CSF. No edema or contrast enhancement +++. Complicated cysts: peri-focal edema and rim enhancement +++. MR spectroscopy shows: Markedly elevated pyruvate, elevated succinate, acetate, alanine peaks, and lipid-lactate peak at 1.33 ppm. Differential Diagnosis: o Arachnoid cyst. o Epidermoid cyst. o Neurocysticercosis. Page 13 of 40

14 13- Toxoplasmosis: Toxoplasmosis is caused by toxoplasma gondii, an intracellular protozoan that is found worldwide. Opportunistic infection common in immunocompromised patients. Clinical presentation : Encephalitis, chorioretinitis Imaging (Fig.17): o Location: Basal ganglia+++, Corticomedullary junction, white matter, Periventricular. o On unenhanced CT images: Multiple hypoattenuating or isoattenuating lesions (solitary lesion may be seen). Surrounding vasogenic edema and mass effect are common. o On contrast-enhanced CT images: Thin, smooth, or poorly defined rim of enhancement; solid eccentric nodular enhancement; or no enhancement. o T1: Hypointense but a peripheral Hyperintensity may be seen, a feature that helps distinguish toxoplasmosis from lymphoma. o T2 and FLAIR images: High or mixed signal intensity. o On diffusion-wi: Peripheral hyperintensity in the presence of hemorrhage within their walls; However, restricted diffusion within the central portion of the lesion, a finding in pyogenic abscesses, is uncommon. o On contrast-enhanced T1-WI: Rim like enhancement of lesions may be seen, often with a surrounding edema. Differential Diagnosis: o Lymphoma+++; o Pyogenic abscess. 14- Ameobic brain abscess: Amoebiasis is a common infection caused by the protozoon Entamoeba histolytica that infects the large intestines of humans. Page 14 of 40

15 Amebic abscess of the brain is commonly an extension of pre-existing amebiasis in extraintestinal viscera but maybe a direct hematogenous extension from the colon (Amebic encephalitis:< 1% of amebiasis patients). Cerebral amebiasis is a rare cause of brain abscess. Clinical presentation: Headache, fever, seizures,increased intracranial pressure, coma. Imaging: Amebiasis, can cause both unilocular and complex intraparenchymal cysts with or without accompanying meningoencephalitis. Location: frontal lobes (Fig.18), basal ganglia +++ Complex conglomerate cysts with thick enhancing rims and striking adjacent edema are common. Diagnosis is made directly by examining tissue for amebic trophozoites. Differential Diagnosis : Primary or metastatic neoplasm; Other parasitic brain abscess. 15- Tuberculosis abscess: Definition: Infection by Mycobacterium tuberculosis (TB), an acid-fast bacillus. Typically causes tuberculous meningitis (TBM) and/or localized CNS infection, tuberculomas. Best diagnostic clue: o Basilar meningitis + extracerebral TB (pulmonary). o Meningitis + parenchymal lesions highly suggestive. Imaging (Fig.19,20,21): Location: o Typically parenchymal, supratentorial (often parietal lobes). Page 15 of 40

16 o Infratentorial lesions are less common, can involve brainstem (up to 8%). Size: Tuberculomas range from 1 mm to 6 cm Tuberculoma morphology: o Round or oval mass. o Solitary or multiple (more common). CT: o Hypodense to hyperdense round or Lobulated nodule / mass with moderate to marked edema. o Solid or ring-enhancing. o Ca++: uncommon (20%). MRI: o Noncaseating granuloma: Hypointense to brain. o Caseating granuloma with solid center: Hypointense or isointense to brain. Differential diagnosis: o Other granuloma, parasite, bacteria. o Pyogenic abscess often has more edema. 16- Pyogenic abscess: Focal pyogenic infection of the brain parenchyma, typically bacterial; Four pathologic stages: Early cerebritis, late cerebritis, early capsule, late capsule. Imaging (Fig.22,23): Location: Typically supratentorial, but may occur infratentorial (> 14%). Frontal and parietal lobes +++, gray-white junction (hematogenous). Anterior and middle cerebral artery distributions +++. o Size: Variable, 5 mm to several cm. o Morphology: Smooth, ring-enhancing lesion. o Imaging varies with stage of abscess development. o Early capsule: Well-defined, thin-walled enhancing rim. Page 16 of 40

17 o Ring-enhancing lesion with restricted diffusion (low ADC). o T2 hypointense abscess rim with surrounding edema. o Gas-containing abscess rare. Differential Diagnosis : o Primary or metastatic neoplasm o Resolving hematoma. o Demyelination. o Subacute infarct. Page 17 of 40

18 Images for this section: Fig. 1: Fig.1 Fig. 2: Fig.2 Page 18 of 40

19 Fig. 3: Fig.3 Fig. 4: Fig.4 Page 19 of 40

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22 Fig. 7: Fig.7 Fig. 8: Fig.8 Fig. 9: Fig.9 Page 22 of 40

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36 Table 1: Table.1 Kimura H et al. Neurocysticercosis: radiologic-pathologic correlation.rg Oct; 30(6): Page 36 of 40

37 Fig. 25: Diagram.2 Page 37 of 40

38 Conclusion Cystic intracranial benign masses are frequently observed on our daily practice. So a careful review of topographical and morphological features presents a big help to narrow the differential diagnosis list. Page 38 of 40

39 Personal Information Page 39 of 40

40 References 1. AG OSBORN, SI BLASER, KL SALZMAN. DIAGNOSTIC IMAGING: BRAIN. 1ST ED. SALT LAKE CITY. AMIRSYS F. BONNEVILLE, F. CATTIN, J.-F. BONNEVILLE, G. JACQUET, G. VIENNET, D. DORMONT. KYSTES DE LA POCHE DE RATHKE. J.NEURORADIOL.2003; 30: HOANG KY, NGUYEN VAN CHAP. ASPECTS RADIOCLINIQUES DE LA CYSTICERCOSE CÉRÉBRALE ET MUSCULAIRE. J. NEURORADIOL., 2000, 27, ANNE G. OSBORN. MICHAEL T. PREECE. INTRACRANIAL CYSTS: RADIOLOGICPATHOLOGIC CORRELATION AND IMAGING APPROACH. RADIOLOGY: VOLUME 239: NUMBER 3-JUNE M DUCHÊNE(1)(2), F BENOUDIBA(2),, C IFFENECKER(2),, M HADJ-RABIA. LA NEUROCYSTICERCOSE. JOURNAL DE RADIOLOGIE 1999; 80: J. ELOUNDOU, E. MBONDA, L. DONGMO, V. AVDEEVA, C. NGONDE SENDE, CYSTICERCOSE MULTIKYSTIQUE INTRACEREBRALE A PROPOS D'UNE OBSERVATION. MÉDECINE D'AFRIQUE NOIRE : 1998, 45 (10). 7. O. BOUCHAUD. PARASITOSES GRAVES DU SYSTÈME NERVEUX CENTRAL. RÉANIMATION 13 (2004) OSBORN AG. NEURENTERIC CYST. IN: DIAGNOSTIC IMAGING: BRAIN. SALT LAKE CITY, UTAH: AMIRSYS, 2004; I PATANKAR TF, MITRA D, VARMA A, SNOWDEN J, NEARY D, JACKSON A. DILATION OF THE VIRCHOW-ROBIN SPACE IS A SENSITIVE INDICATOR OF CEREBRAL MICROVASCULAR DISEASE: STUDY IN ELDERLY PATIENTS WITH DEMENTIA. AM J NEURORADIOL. 2005;26: Page 40 of 40