Jerry M.E. Kovoor

Eccentric Target Sign in Cerebral Toxoplasmosis – neuropathological correlate to the imaging feature

Cerebral toxoplasmosis remains one of the most common focal brain lesions in patients with acquired immune deficiency syndrome (AIDS). Diagnosis is a challenge because on cranial imaging it closely mimics central nervous system lymphoma, primary and metastatic central nervous system (CNS) tumors, or other intracranial infections like tuberculoma or abscesses. A magnetic resonance imaging (MRI) feature on postcontrast T1‐weighted sequences considered pathognomonic of toxoplasmosis is the “eccentric target sign.” The pathological correlate of this imaging sign has been speculative. Herein we correlate the underlying histopathology to the MR feature of eccentric target sign in a patient with autopsy‐proven HIV/AIDS‐related cerebral toxoplasmosis. The central enhancing core of the target seen on MRI was produced by a leash of inflamed vessels extending down the length of the sulcus that was surrounded by concentric zones of necrosis and a wall composed of histiocytes and proliferating blood vessels, with impaired permeability producing the peripheral enhancing rim. J. Magn. Reson. Imaging 2010;31:1469–1472.

Pyruvate: an in vivo marker of cestodal infestation of the human brain on proton MR spectroscopy.

To study intracranial cestodal cysts using in vivo proton magnetic resonance spectroscopy (1H MRS) in an effort to identify metabolite(s) that may help in recognizing the parasitic etiology and, perhaps, viability of such tapeworm cysts. Cestodal infestations of the human central nervous system (CNS)—cysticercosis and hydatidosis—are not rare. Identification of a scolex is considered diagnostic of cysticercosis on imaging. In its absence, however, the features are non‐specific.

Cranial MRI in Acute Hyperammonemic Encephalopathy

Cranial magnetic resonance imaging was performed in three cases of acute hyperammonemic encephalopathy with three diverse etiologies: infantile citrullinemia, acute hepatic encephalopathy, and proximal urea cycle disorder. All three patients exhibited diffuse extensive cortical signal changes and swelling. Neurologic outcome was poor in all three cases. Knowledge of the magnetic resonance imaging findings of hyperammonemic encephalopathy may help in early diagnosis and treatment and could influence the neurologic outcome.

Is total excision of spinal neurenteric cysts possible

Spinal neurenteric cysts are intradural cystic lesions. These represent a part of the spectrum of developmental anomalies. These are rare lesions. Most of the data in literature is review of case reports. This made us evaluate our results of 23 cases and review the literature. This is a retrospective study of 23 patients managed at our institute over 20 years. The slides were retrieved and histopathological features studied. Twenty patients were less than 30 years old and 21 were males. Follow-up was available for 21 patients with mean duration of 71 months (range 2 months to 23 years). The typical presentation was backache with progressive neurological deficits pertaining to the level. Atypical presentations as acute onset, recurrent episodic events and aseptic meningitis were also noted. The cervicothoracic region was the most common site. 16 patients had cyst in intradural extramedullary plane and seven had intramedullary location. Associated vertebral anomalies as hemivertebrae, Klippel – Feil and spina bifida were noted in seven patients. There were two histological types of cysts with no correlation between the type of cysts and associated vertebral anomalies and extent of outcome. Partial excision though had higher risk of recurrence, was not associated with poorer outcome. Dorsal approach is an acceptable route with reasonably good results for this lesion. Spinal neurenteric cysts present at younger age with varied clinical presentations. These are commonly located intradurally ventral to the cord. Histological types have no effect on the outcome. Total excision is the choice of treatment. However, partial excision is a feasible option in intramedullary lesions and when significant adhesions occur. Although associated with higher risk of recurrence, the outcome is still good in these patients on re-excision.

Descriptive study of acute disseminated encephalomyelitis and evaluation of functional outcome predictors.

BACKGROUND Outcome following Acute Disseminated Encephalomyelitis (ADEM) is variable and there are only limited studies from India. AIM The study aims to evaluate the predictors of functional outcome in a cohort of patients with ADEM. SETTING Tertiary-care teaching hospital. MATERIALS AND METHODS Patients admitted with the diagnosis of ADEM from 1999 to 2004 have been included. Clinical features and radiological findings were evaluated. Functional outcome at discharge was scored using modified Rankin Scale and patients were followed up regularly. STATISTICAL ANALYSIS Chi-Square test or Fishers exact test, and Students t test for comparison of categorical and continuous variables, respectively, and logistic regression for multivariate analysis. RESULTS Sixty-one patients were evaluated (mean age 22+/-15.9 years, 1-65). Fifty-two patients had preceding febrile illness or vaccination with mean 9.1+/-12.5 days interval to first neurological symptom. Non-specific febrile illnesses were the commonest trigger. Commonest findings were motor signs (n=41), impaired consciousness (n=33), bladder symptoms (n=21), ataxia (n=15), and seizures (n=14). Between adult (mean age 30.1+/-13.1 years, 13-65, n=38), and pediatric (mean age 6.2+/-2.8 years, 1-12, n=23) patients, language disturbances were more common in the latter (P=0.047). MR imaging (n=35) demonstrated lesions mostly in frontoparietal white matter (n=23) and thalamus (n=15). Nine patients expired. Patients with poor functional outcome at discharge more often had impaired consciousness (P=0.038) and seizures (P=0.06). At follow-up (n=25), deficits included motor signs (n=15) and bladder symptoms (n=5). CONCLUSIONS ADEM has a wide range of neurological presentations and language disturbances are more common in pediatric patients. The presence of impaired consciousness, and possibly seizures, predict poor functional outcome at hospital discharge.

Natural history of solitary cerebral cysticercosis on serial magnetic resonance imaging and the effect of albendazole therapy on its evolution.

AIM To describe the evolution of imaging characteristics of solitary cerebral cysticercal lesions (SCCL) on serial MRI, and to study the effect of treatment with albendazole. DESIGN Randomised controlled prospective trial. METHODS AND MATERIAL 123 patients with new-onset seizures and SCCL on contrast MRI were randomised to treatment with albendazole and followed with up to five serial MRIs. RESULTS 81 patients (M - 41, F - 40) with mean age of 19.6+/-11.7years and 4 or 5 serial MRI were included in the analysis. Analysis was performed on 356 MRIs. Scolex was seen in 61.9% of patients in postcontrast T1 sequence in the first MRI study, and there was a significant drop in visibility from the next scan onwards. Cyst contents were initially T1-hypointense and T2-hyperintense with inversion on FLAIR in 30.8% and later scans showed T2-hypointensity. Cyst wall characteristics changed significantly from initially T2-hypointensity to later hyperintense rim. Initial scan revealed perilesional oedema in 98.5%, which is resolved by the second scan. Around 17.5% showed subtle perilesional T2-hyperintensity in follow-up scans. Enhancement pattern changed significantly from ring to disc, and later to non-enhancement. Initially, 69.7% lesions were in colloid-vesicular stage. Lesions moved through subsequent stages of cyst degeneration: time needed for this process is described. Imaging characteristics, both on the first and on subsequent scans, did not differ between albendazole and control groups. CONCLUSIONS Evolution of SCCL follows a predictable sequence corresponding to morphologic stages described earlier, taking over a year to complete. Contrast enhancement decreases as degeneration progresses, but some calcific lesions continue to enhance. Albendazole therapy may hasten resolution of inflammation around the lesion but affects neither the morphology of the cysticercus nor the process of degeneration and subsequent healing.

Supratentorial and cerebellar liponeurocytomas: report of four cases with review of literature

Liponeurocytoma is not exclusive to the cerebellar or fourth ventricular location. Since its inclusion in the central nervous system tumor classification in 2000, six cases with similar radiological, histomorphological and immunohistochemical features have also been described in the lateral ventricles. In the present study, we report clinical, radiological and pathological findings of three supratentorial and one cerebellar liponeurocytoma from our records, evaluated with an extensive panel of immunohistochemistry, and review published cases in the literature. The immunohistochemical pattern of supratentorial and infratentorial liponeurocytomas are almost identical, which indicates that these tumors are homologous.

Cerebral phaeohyphomycosis caused by Scytalidium dimidiatum: a case report from India

We report a case of cerebral phaeohyphomycosis caused by Scytalidium dimidiatum (synanamorph Nattrassia mangiferae) in a young, apparently immunocompetent Indian male. Etiological diagnosis was made by recovery of the fungus in culture and histopathological examination. The infection proved fatal despite aggressive antifungal therapy.

Serum vitamin B12 deficiency and hyperhomocystinemia: a reversible cause of acute chorea, cerebellar ataxia in an adult with cerebral ischemia.

Patients with vitamin B12 deficiency have protean neurological manifestations that are often insidious. Acute onset of cerebellar dysfunction and extrapyramidal manifestations like dystonia and chorea are rather uncommon in adults. We describe a patient who manifested with acute onset of language dysfunction, chorea and ataxia. There was no history of hypertension, diabetes or ischemic heart disease. He had low serum vitamin B12 and elevated serum homocystine levels. He improved dramatically following B12 replacement therapy. Our patient provides insight into the pathophysiological mechanism of this rare manifestation. Further the importance of considering vitamin B12 deficiency, in country like India, where vegetarian food practice is quite common, is being emphasized.

Randomized controlled trial of albendazole in new onset epilepsy and MRI confirmed solitary cerebral cysticercal lesion: Effect on long-term seizure outcome ☆

No trials to date have focused on long-term seizure outcome in solitary cerebral cysticercal lesion (SCCL), which is believed to produce a relatively benign form of epilepsy. This is a prospective randomized controlled study to evaluate the effect of Albendazole on long-term seizure outcome in patients with MRI-confirmed solitary cerebral cysticercal lesion (SCCL). One hundred and twenty-three patients with new-onset seizures and SCCL on contrast MRI were randomized to treatment with albendazole and followed for up to five years with serial MRI and clinical evaluation. At final analysis 103 patients (M-54, F-49) with a mean age of 18.6+/-10.7 years and follow-up period more than 12 months were included. The mean follow-up duration was 31.4+/-14.8 months (12-64). At one month follow-up more patients receiving albendazole were seizure-free (62% versus 49% for controls). Subsequently there was no significant difference in overall seizure outcome between the two groups. There was no correlation between seizure semiology, albendazole therapy and long-term seizure outcome. Baseline MRI showed active lesions in all; 23% remained active at 12 months with no difference between the albendazole and control groups. Patients whose lesions resolved at 12 months showed better seizure outcome. Reduction in mean cyst area was greater in the albendazole group as compared to the controls and the difference at six months was significant (p<0.05). At three months follow-up perilesional edema also resolved faster in albendazole group (p<0.05). Thus, albendazole did not alter the long-term seizure outcome in patients with SCCL and epilepsy. However, albendazole hastened resolution of SCCL on MRI, but interestingly 23% of lesions were still active 12 months after treatment.