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pleomorphism. However, 30% recur and up to 20% may undergo anaplastic transformation.5–8 Anaplastic features at first presentation with meningeal dissemination have been reported.9 Several histopathological features have been shown to be poor prognostic factors: increased mitotic activity, higher MIB-1 and proliferating cell nuclear antigen (PCNA) labelling indices have been associated with recurrence and poorer prognosis.5,10–13 Necrosis has also been demonstrated to be a bad prognostic factor.5,14 Abundant lymphocytic infiltration is associated with benign biological behaviour.10 In our patient, the presence of necrosis and infarction identified radiologically and histopathologically is surprising in view of the low MIB index. Advanced age may also portend a poor prognosis, and atypical variants of PXA have been described in the elderly.15 Chakrabarty et al. reported two cases of malignant transformation in a 49-year-old and a 40-year-old man.8 Necrosis and frequent mitotic figures were found histologically. Bucciero et al. reported the case of a 65-yearold man with atypical PXA exhibiting areas of necrosis, increased cellularity and brisk mitotic activity. The patient died 22 months after surgery from tumour regrowth in spite of adjuvant fractionated external beam radiation therapy.3 Our patient was a 76-year-old woman presenting with significant mass effect, who had rapid disease progression and overall survival of only 6 months in spite of surgery and radiation therapy. Although advanced age may be an independent risk factor for poor outcome, the rapidity of progression of this case suggests that is PXAs in the elderly may behave in a more aggressive fashion. 4. Conclusion Pleomorphic xanthoastrocytoma is a rare astrocytic tumour that typically affects children and young adults, and which has a good prognosis. However, presentation in older patients may portend a poor prognosis. Our patient presented with intracranial hypertension and focal deficits, and the radiological features of a glioblastoma. Although they are a rare and benign tumour type, PXA in the elderly tend to be more malignant, may radiologically mimic malignant neoplasm is and have a poor prognosis.
Acknowledgements We would like to acknowledge Dr Jennifer Teo and Mr Selamat Wata for providing us with histopathological input and slides. References 1. Kepes JJ, Rubinstein LJ, Eng LF. Pleomorphic xanthoastrocytoma: a distinctive meningocerebral glioma of young subjects with relatively favourable prognosis: a study of 12 cases. Cancer 1979;44: 1839–52. 2. Russell DS, Rubinstein LJ. Pathology of Tumors of the Nervous System. 5th edn. London: Edward Arnold; 1989. 3. Bucciero A, De Caro M, De Stefano V, et al. Pleomorphic xanthoastrocytoma: clinical, imaging and pathological features of four cases. Clin Neurol Neurosurg 1997;99:40–5. 4. Perry A, Giannini C, Scheithauer BW, et al. Composite pleomorphic xanthoastrocytoma and ganglioglioma: report of four cases and review of the literature. Am J Surg Pathol 1997;21:763–71. 5. Bayindir C, Balak N, Karasu A, et al. Anaplastic pleomorphic xanthoastrocytoma. Childs Nerv Syst 1997;13:50–6. 6. Korshunov A, Golanov A. Pleomorphic xanthoastrocytomas: immunohistochemistry, grading and clinico-pathological correlations. An analysis of 34 cases from a single institute. J Neurooncol 2001;52:63–72. 7. Cervoni L, Salvati M, Santoro A, et al. Pleomorphic xanthoastrocytoma: some observations. Neurosurg Rev 1996;19:13–6. 8. Chakrabarty A, Mitchell P, Bridges LR, et al. Malignant transformation in pleomorphic xanthoastrocytoma – a report of two cases. Br J Neurosurg 1999;13:516–9. 9. Lubansu A, Rorive S, David P, et al. Cerebral anaplastic pleomorphic xanthoastrocytoma with dissemination at first presentation. Childs Nerv Syst 2004;20:119–22. 10. Sugita Y, Shigemori M, Okamoto K, et al. Clinicopathological study of pleomorphic xanthoastrocytoma: correlation between histological features and prognosis. Pathol Int 2000;50:703–8. 11. Macaulay RJ, Jay V, Hoffman HJ, et al. Increased mitotic activity as a negative prognostic indicator in pleomorphic xanthoastrocytoma. Case report. J Neurosurg 1993;79:761–8. 12. Prayson RA, Morris HH III. Anaplastic pleomorphic xanthoastrocytoma. Arch Path Lab Med 1998;122:1082–6. 13. Leonard N, Alcutt DA, Farrell MA. Fatal pleomorphic xanthoastrocytoma with meningeal gliomatosis. Histopathology 1998;32:375–8. 14. Pahapill PA, Ramsay DA, Del Maestro RF. Pleomorphic xanthoastrocytoma: case report and analysis of the literature concerning the efficacy of resection and the significance of necrosis. Neurosurgery 1996;38:822–8. 15. MacKenzie JM. Pleomorphic xanthoastrocytoma in a 62 year-old male. Neuropathol Appl Neurobiol 1987;13:481–7.
doi:10.1016/j.jocn.2006.09.012
MRI in non-alcoholic Wernicke’s encephalopathy Rahul Rathakrishnan a,*, Einar-Wilder Smith b a
Division of Neurology, National University Hospital, 5 Lower Kent Ridge Road, Singapore 119074, Singapore b Division of Neurology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore Received 22 November 2006; accepted 8 March 2007
*
Corresponding author. Tel.: +65 67724353; fax: +65 67794112. E-mail addresses:
[email protected] (R. Rathakrishnan).
Case Reports / Journal of Clinical Neuroscience 15 (2008) 478–480
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Abstract Wernicke’s encephalopathy (WE) is a potentially reversible disorder. It is often not considered in non-alcoholic patients unless MRI demonstrates lesions in the appropriate sites. However, specific MRI sequences only highlight some areas of abnormality and hence WE may not be considered unless a more complete study is performed and this is highlighted in the case described herein. The neuropathological basis for the imaging findings is also discussed. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Wernicke’s encephalopathy; MRI
1. Introduction Non-alcoholic Wernicke’s encephalopathy (WE) is an uncommon condition that is eminently treatable. Specific modalities of MRI serve as useful diagnostic tools. We report a patient in whom the diagnosis was made following neuroimaging. 2. Case report A 53-year-old man with stable chronic schizophrenia treated with zuclopenthixol depot injections was admitted when he was found at home in a disheveled and stuporous state. He had been vomiting for several days prior to this. There was no history of alcohol ingestion and prior to his current illness, he did not suffer from malnutrition. On arrival he was obtunded and had coarse bilateral gazeevoked nystagmus. CT of the brain and cerebrospinal fluid studies were unremarkable, and viral and bacterial cultures were negative. Routine blood investigations including liver function tests were normal. Fig. 1A shows MRI diffusionweighted images (DWI) that demonstrate restricted diffusion of the medial thalami bilaterally (Fig. 1Aiii). However, echoplanar fluid-attenuated inversion recovery (FLAIR) imaging demonstrated hyperintensities in the periaqueductal midbrain and grey matter as well as the walls of the third ventricle (Fig. 1Bi,ii) which were not apparent on
DWI. The patient was given intravenous thiamine for 10 days with marked clinical and radiological improvement. 3. Discussion Thiamine is an important co-factor in glucose and oxidative metabolism. It is essential in maintaining osmotic gradients across cell membranes.1 WE is due to a deficiency of thiamine. Necrosis, and astroglial and microglial proliferation occur in regions of the brain that have copious thiamine-dependant metabolism such as the pontine and mesencephalic tegmentum, and the thalamic and mamillary bodies.1 This results in the classical triad of ophthalmoplegia, ataxia and disturbance of consciousness.1–3 It is recognized in chronic alcoholics who are malnourished. Non-alcoholic WE is an uncommon disorder and should be considered in patients who present with confusion, as it is potentially reversible.1 Importantly, malnourishment is not always evident at the time of presentation. It may also occur as an iatrogenic complication when susceptible patients are administered intravenous dextrose without parenteral thiamine. MRI is a useful diagnostic tool premortem.4 In patients who do not present typically, the diagnosis is often only suspected after MRI is performed. The findings described are hyperintense signals on T2-weighted and FLAIR images in the periaqueductal regions and bilateral medial
Fig. 1. MRI in a non-alcoholic patient with Wernicke’s encephalopathy. (A) MRI axial diffusion weighted images that demonstrate restricted diffusion of the medial thalami bilaterally. (B) Corresponding slices using echoplanar fluid-attenuated inversion recovery that demonstrate hyperintensities in the periaqueductal midbrain grey matter and walls of the third ventricle.
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thalami. Atrophy of the mamillary bodies and cerebellar vermis are also reported.1 DWI has been cited as a superior modality of MRI due to the shorter acquisition time.5 However, DWI preferentially demonstrates lesions in the thalami but not in the periaqueductal regions, which are highlighted on T2-weighted and FLAIR images.2 This is thought to be due to the difference in the degree of oedema.2 A neuropathological study of non-alcoholic WE has shown that neuronal change appears to predominate in the thalamic regions with relative preservation in the periventricular regions and mamillary bodies, which may account for this interesting radiological feature as observed in our patient.4 Thalamic involvement in WE correlates with the extent of disturbance in consciousness and may be indicative of a more severe disease.2 Our case highlights that while the clinical index of suspicion should be high in such patients, neuroimaging is a useful adjunctive diagnostic tool and employing several modalities of MRI better delineates the brain lesions seen in WE. The DWI highlighted the thalamic lesions, whereas the periaqueductal lesions were demonstrated on the FLAIR sequence using the more rapid echoplanar acquisition. The routine FLAIR sequence was not interpretable in our patient due to gross movement artifacts. Echoplanar-acquired FLAIR should be considered in pa-
tients who are unable to tolerate a prolonged period in the scanner. Parenteral high-dose thiamine can arrest disease progression and reverse the neurological deficits within hours, highlighting the need for early diagnosis.3 A carefully tailored MRI with the appropriate sequences can provide useful information that can be of particular importance in aiding in the diagnosis of atypical cases of WE. References 1. Zhong C, Jin L, Fei G. MR imaging of nonalcoholic Wernicke encephalopathy: A follow-up study. Am J Neuroradiol 2005;26: 2301–5. 2. White ML, Zhang Y, Andrew LG, et al. MR imaging with diffusionweighted imaging in acute and chronic Wernicke encephalopathy. AJNR Am J Neuroradiol 2005;26:2306–10. 3. Yamamoto T. Alcoholic and non-alcoholic Wernicke’s encephalopathy. Be alert to the preventable and treatable disease. Intern Med 1996;35:754–5. 4. Gui QP, Zhao WQ, Wang LN. Wernicke’s encephalopathy in nonalcoholic patients: clinical and pathologic features of three cases and literature reviewed. Neuropathology 2006;26:231–5. 5. Kashihara K, Irisawa M. Diffusion weighted magnetic resonance imaging in a case of acute Wernicke’s encephalopathy. J Neurol Neurosurg Psychiatry 2002;73:181.
doi:10.1016/j.jocn.2007.03.007
Pituitary apoplexy as a cause of internal carotid artery occlusion Seref Dogan *, Hasan Kocaeli, Faruk Abas, Ender Korfali Department of Neurosurgery, Uludag˘ University School of Medicine, Gorukle, 16059 Bursa, Turkey Received 6 July 2006; accepted 20 August 2006
Abstract Occlusion of intracranial arteries by pituitary apoplexy with resulting infarction is a rare occurrence. A 50-year-old man who presented with a history of sudden onset of frontal headache and visual impairment was admitted to another medical centre and MRI revealed a non-enhancing sellar lesion with suprasellar and infrasellar extension. Thereafter, the patient’s consciousness deteriorated progressively and he showed signs of herniation; he was then referred to our centre for further evaluation. CT scanning revealed infarction of the left internal carotid artery territory. Transcranial resection of the tumour followed by a large decompressive craniotomy restored the blood flow in the internal carotid artery. Histological examination revealed the tumour to be a pituitary adenoma that contained formed blood elements. The patient’s neurological status did not improve and he died on the ninth postoperative day despite vigorous treatment for controlling intracranial pressure. This case study documents a rare presentation of pituitary apoplexy that caused signs of raised intracranial pressure due to mechanical obstruction of an internal carotid artery with resulting infarction. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Cerebral infarction; Decompressive craniectomy; Pituitary apoplexy; Vascular occlusion
*
Corresponding author. Tel.: +90 224 4428081; fax: +90 224 4429263. E-mail addresses:
[email protected] (S. Dogan).
