188 Correspondance d’installation brutale responsable d’une diplopie. Le scan-
ner cérébral initial révéla une hémorragie mésencéphalique.
Une IRM cérébrale (séquences FLAIR, T2*, diffusion, SE T1) réalisée trois mois plus tard dans le cadre du contrôle évo- lutif montra, sur la séquence en écho de gradient, un signal hétérogène dans le mésencéphale évoquant une hémorra- gie ancienne (Fig. 1) ainsi que de multiples hyposignaux de petite taille, cortico-sous-corticaux, bilatéraux, sus- et sous-tentorielles, en rapport avec des microhémorragies chroniques (microbleeds).
Les microbleeds ont été décrits dans de nombreuses pathologies[3,6]. Ils sont notamment très souvent retrou- vés dans les maladies vasculaires cérébrales. La prévalence desmicrobleedsest ainsi estimée à 60 % chez des patients ayant un accident vasculaire cérébral (AVC) hémorragique non traumatique et à 34 % chez ceux ayant un AVC isché- mique, en comparaison à une prévalence de 5 % chez des adultes sains[3]. Dans le contexte des maladies vasculaires cérébrales, il existe une corrélation nette entre hyperten- sion artérielle et microbleeds [3]. Ces derniers sont, par ailleurs, associés à de la leuco-araïose et des lacunes intra- parenchymateuses (maladies des petites artères)[3,5]. Les microbleedsont été décrits dans d’autres affections que les AVC, telles que la maladie d’Alzheimer, les traumatismes crâniens et la cavernomatose [3,6]. Les séquences d’IRM pondérées en écho de gradient T2sont les séquences les plus sensibles pour la détection d’hémorragie cérébrale[4], en particulier, pour des hémorragies cérébrales de petite taille qui peuvent rester non détectées par d’autres techniques radiologiques[6].
Les principales manifestations neuroradiologiques décrites au cours du purpura thrombocytopénique throm- botique sont des infarctus cérébraux et des plages parenchymateuses d’œdème cérébral réversible [2]. Ces plages œdémateuses sont hyper-intenses en séquence pondérée T2 et concernent habituellement la substance blanche des régions parieto-occipitales, la partie pos- térieure des lobes frontaux, le pont et le cervelet. En IRM, ces anomalies ressemblent aux anomalies visualisées dans la leuco-encéphalopathie postérieure réversible. En outre, les patients avec un purpura thrombocytopénique thrombotique peuvent présenter des hématomes intra- crâniens, parfois volumineux. Le cas présent montre que les microbleeds intracérébraux localisés dans les régions cortico-sous-corticales peuvent également être associés au purpura thrombocytopénique thrombotique.
Références
[1] Austin S, Cohen H, Losseff N. Haematology and neurology.
J Neurol Neurosurg Psychiatry 2007;78:334—41.
[2] Bakshi R, Shaikh ZA, Bates VE, Kinkel PR. Thrombotic throm- bocytopenic purpura: brain CT and MRI findings in 12 patients.
Neurology 1999;52:1285—8.
[3] Cordonnier C, Al-Shahi Salman R, Wardlaw J. Sponta- neous brain microbleeds: systematic review, subgroup ana- lyses and standards for study design and reporting. Brain 2007;130:1988—2003.
[4] Fazekas F, Kleinert R, Roob G, Kleinert G, Kapeller P, Schmidt R, et al. Histopathologic analysis of foci of signal loss on gradient- echo T2*-weighted MR images in patients with spontaneous intracerebral hemorrhage: evidence of microangiopathy-related microbleeds. AJNR Am J Neuroradiol 1999;20:637—42.
[5] Tsushima Y, Aoki J, Endo K. Brain microhemorrhages detected on T2*-weighted gradient-echo MR images. AJNR Am J Neuroradiol 2003;24:88—96.
[6] Viswanathan A, Chabriat H. Cerebral microhemorrhage. Stroke 2006;37:550—5.
D.R. Rutgers∗ G. Saliou D. Ducreux Service de neuroradiologie, CHU de Bicêtre, 78, rue du Général-Leclerc, 94270 Le Kremlin-Bicêtre, France
∗Auteur correspondant.
Adresse e-mail :[email protected](D.R. Rutgers) Disponible sur Internet le 21 d´ecembre 2007
doi: 10.1016/j.neurad.2007.10.006
Primary hydatid cyst of the neck Kyste hydatique primaire de la nuque
We report on the case of a 7-year-old boy, admitted with a 6-month history of a slowly growing occipitocervical mass that was painless and without fever or radicular pain. On examination, this palpable, round, fluctuating mass measu- red 3×4 cm, with no local inflammatory response or spasm of the cervical muscles. Physical and neurological exami- nations revealed no abnormalities. Craniocervical MRI scans showed a spherical cystic lesion in the posterior soft tissue at the craniovertebral junction, with intensity unit values approaching those for cerebrospinal fluid on T1- and T2- weighted sequencing. The cystic lesion was round and well delineated by a thin wall that showed no enhancement after injection of contrast (Fig. 1). Both the clinical and laboratory examinations were normal. The cyst was surgically removed intact via a posterior approach (Fig. 2); the outcome was good, with no recurrence after 10 months. Histopathology confirmed a hydatid cyst, and detailed investigations failed to reveal any evidence of hydatid disease elsewhere in the body.
Echinococcosis is a human disease caused by accidental parasitic infestation by the larval form of the dog tapeworm Taenia echinococcus. Humans are infected through oral ingestion of the tapeworm ova via contaminated foods or direct contact with carnivores. Only the tapeworm embryos that successfully pass through the hepatic and pulmonary filtering systems are able to reach other organs through the systemic circulation. Extrahepatic involvement of hyda- tid cyst has been reported, including the spleen, kidney, heart, bones, muscles and cranium, but echinococcosis of soft tissue represents less than 3% of all hydatid disease[1].
Cervical involvement in hydatid disease is rare, occurring in less than 0.5% of such patients[3]and localization to the neck is even more unusual, with only a few cases reported in the literature, even in countries where echinococcal infesta- tion is endemic[5]. At this site, an isolated infestation with no history of cystic rupture elsewhere in the circulation, as seen in our case, is particularly unusual.
Correspondance 189
Figure 1 T1-weighted MRI without gadolinium contrast injec- tion shows a hypo-intense cystic mass (3×4 cm) in the posterior soft tissue at the craniovertebral junction.
Figure 1 IRM cervicale en T1 sans injection de gadolinium, montrant un processus kystique hypo-intense (3×4 cm), situé dans les parties molles postérieures au niveau de la jonction craniovértébrale.
Figure 2 Perioperative view of cervical cyst being removed.
Figure 2 Vue peropératoire de l’énucléation du kyste cervical.
Neither clinical manifestations nor radiological pictures are pathognomonic of this form of solitary hydatid cyst in the neck[2]. It often presents as a simple soft-tissue mass, with slow compression of the surrounding tissue[4]. Ultrasound and CT scans are helpful for visualization of the cyst, as a low-density central area and no ring enhancement following contrast injection, and no surrounding edema, is typical.
The cystic fluid has a Hounsfield number similar to that of cerebrospinal fluid. MRI, more than CT scanning, can pro- vide the best anatomical—topographical evaluation before surgery[6].
The treatment of soft-tissue hydatid cysts is surgi- cal and, to be successful, the operation must completely remove the echinococcal cyst without spilling its contents.
Indeed, rupture of the cysts can result in fever, urticaria and anaphylactic shock, as well as cystic dissemina- tion.
In reporting this case, we wish to draw attention to the possibility of the diagnosis of hydatid disease in the case of a large cystic mass of the neck region.
References
[1] Cangiotti L, Muiesan P, Begni A. Unusual localizations of hydatid disease: an 18-year experience. G Chir 1994;15:83—6.
[2] Celik A, Turanli M, Kutun S, Delibasi T, Mengi N, Comert E, et al.
Unusual location of hydatid cyst: soft tissue mass in the neck.
Eur Arch Otorhinolaryngol 2006;263(12):1147—50.
[3] Eroglu A, Atabekoglu S, Kocaoglu H. Primary hydatid cyst of the neck. Eur Arch Otorhinolaryngol 1999;256:202—4.
[4] Gangopadhyay K, Abuzeid MO, Kfoury H. Hydatid cyst of the pterygopalatine-infratemporal fossa. J Laryngol Otol 1996;110:978—80.
[5] Ijaz A, Zia-ul-Haq, Imtiaz H. Hydatid cyst of the cervical region in a child. A rare location. Saudi Med J 2004;25:2047—8.
[6] Tekin M, Osma U, Yldiz M, Topcu I. Preauricular hydatid cyst:
an unusual location for echinoccosis. Eur Arch Otorhinolaryngol 2004;261:87—9.
S. Hilmani∗ A. Bertal A. Sami A. Ouboukhlik A. El-Kamar A. El-Azhari Department of Neurological Surgery, UHC Ibn-Rushd, Hassan-II University, Casablanca 20100, Morocco
∗Corresponding author.
Adresse e-mail :[email protected](S. Hilmani) Available online 21 February 2008
doi: 10.1016/j.neurad.2007.10.004
Primary spinal intradural mesenchymal chon- drosarcoma. A pediatric case report
Chondrosarcome mésenchymateux rachidien intradural primitif. À propos d’un cas pédia- trique
Chondrosarcoma is an extremely rare cartilaginous tumor that is typically associated with bone[1]. So, extraskeletal mesenchymal chondrosarcoma is even more unusual. In the central nervous system, the exact origin of intradural chon- drosarcoma remains obscure[2,6]. We present a rare case of primary spinal intradural mesenchymal chondrosarcoma with no bone involvement.
A 13-year-old girl presented with back pain and bilate- ral progressive weakness and numbness of the left lower extremity for two months, but without sphincter dysfunc- tion. Neurological examination revealed paraparesis and loss of sensorimotor function from the T9 level down. Magne-
