Diffuse form of dysembryoplastic neuroepithelial tumour: the histological and immunohistochemical features of a distinct entity showing transition to dysembryoplastic neuroepithelial tumour and ganglioglioma

AIMS

A diffuse variant of dysembryoplastic neuroepithelial tumour (dDNT) has previously been described, which although composed of oligodendroglia-like cells (OLC), astrocytes and mature neurones, lacks the multinodularity and 'specific component' of typical DNT. The dDNT poses a significant challenge to the neuropathologist. This study was undertaken to further characterize the histological and immunohistochemical features of dDNT.

MATERIALS AND METHODS

Review of our archived material from epilepsy surgery identified 16 cases, in which features of dDNT predominated. Their histological and immunohistochemical features, including CD34 and nestin immunohistochemistry, were analysed.

RESULTS

Seven cases had the characteristics of pure dDNT. A further two cases of dDNT showed extension into the white matter with occasional dysplastic neurones. Two additional cases had similar features but with the presence of either single, or multiple small nodular clusters of OLC, in keeping with transition to classical DNT. Five cases showed ganglioglioma-like areas, of which three cases had micronodule formation but with predominant dDNT pattern. In all the cases the dDNT areas showed strong CD34 and less intense nestin immunoreactivity and microglial activation highlighting the full extent of the lesions. There was variable overlap between CD34 and nestin positivity within the micronodular and/or ganglioglioma-like areas.

CONCLUSIONS

Immunoreactivity for CD34 and nestin characterizes the dDNT and helps to distinguish it from other lesions associated with epilepsy. Histological evidence indicative of transition of dDNT to other forms of DNT and ganglioglioma suggests that dDNT might be an early histogenetic form of these glioneuronal tumours.

Pregabalin as adjunctive therapy for partial epilepsy: an audit study in 96 patients from the South East of England

INTRODUCTION

Pregabalin (PGB) was licensed in the EU in 2004 as an adjunctive therapy in partial epilepsy. It is also licensed for neuropathic pain and generalised anxiety.

AIMS

To identify the clinical usefulness and side effects of add-on PGB in out-patient epilepsy clinics.

METHODS

We performed an audit on 96 consecutive patients (44 male) prescribed PGB for refractory epilepsy. Mean follow-up, for those who remained on PGB, was 23 months (range 12-39 months).

RESULTS

Fifty patients remained on PGB, 37 of whom reported clear improvement in seizure frequency. Among these 37 patients, 1 was seizure free for 15 months; 29 had a seizure reduction of >50%; and 7 improved by <50%. Eight patients reported a decrease in seizure severity without change in seizure frequency. Nine patients reported an incidental improvement in anxiety. Side effects were reported by 25 patients out of the 50 patients still on treatment: 12 reported drowsiness or tiredness, 8 weight gain, 7 dizziness, 2 headache, 2 cognitive side effects, 1 irritability, 1 itchiness, 1 anxiety, and 1 transient rash. Among the 46 patients who discontinued treatment, 9 had worsening of seizure frequency, 27 lack of efficacy and 9 intolerable side effects necessitating withdrawal (4 dizziness or drowsiness, 2 weight gain, 1 peripheral oedema, 1 pain in arms and legs, 1 irritability and cognitive side effects). One patient had a seizure related death (probably drowning) within 1 month of starting PGB.

CONCLUSION

Pregabalin seems to be an effective and well-tolerated anti-epileptic drug when used as add-on treatment in patients with refractory partial epilepsy.

Is it worth pursuing surgery for epilepsy in patients with normal neuroimaging?

OBJECTIVE

To determine whether it is worth pursuing surgery for the treatment of epilepsy in patients with normal neuroimaging.

METHODS

Two patient populations were studied: (1) 136 consecutive patients who were surgically treated; (2) 105 consecutive patients assessed with chronically implanted intracranial electrodes within the same period. Sixty patients belonged to both groups, and included all 21 patients who had normal neuroimaging.

RESULTS

There were no differences in the proportion of patients with favourable outcome between those with normal and those with abnormal neuroimaging, irrespective of whether intracranial recordings were required. Among the 19 operated patients with normal neuroimaging, 74% had a favourable outcome (Engel's seizure outcome grades I and II), and among the 93 patients with abnormal neuroimaging, 73% had favourable outcome (p = 0.96). In patients with temporal resections, 92% of the 13 patients with normal neuroimaging had a favourable outcome, whereas among the 70 patients with abnormal neuroimaging, 80% had a favourable outcome (p = 0.44). In patients with extratemporal resections, two of the six patients with normal neuroimaging had a favourable outcome, while 12 of the 23 patients with abnormal neuroimaging had a favourable outcome (p = 0.65). Among the 105 patients studied with intracranial electrodes, five suffered transitory deficits as a result of implantation, and two suffered permanent deficits (one hemiplegia caused by haematoma and one mild dysphasia resulting from haemorrhage).

CONCLUSIONS

It is worth pursuing surgery in patients with normal neuroimaging because it results in good seizure control and the incidence of permanent deficits associated with intracranial studies is low.

Alcoholic skeletal muscle myopathy: definitions, features, contribution of neuropathy, impact and diagnosis

Alcohol misusers frequently have difficulties in gait, and various muscle symptoms such as cramps, local pain and reduced muscle mass. These symptoms are common in alcoholic patients and have previously been ascribed as neuropathological in origin. However, biochemical lesions and/or the presence of a defined myopathy occur in alcoholics as a direct consequence of alcohol misuse. The myopathy occurs independently of peripheral neuropathy, malnutrition and overt liver disease. Chronic alcoholic myopathy is characterized by selective atrophy of Type II fibres and the entire muscle mass may be reduced by up to 30%. This myopathy is arguably the most prevalent skeletal muscle disorder in the Western Hemisphere and occurs in approximately 50% of alcohol misusers. Alcohol and acetaldehyde are potent inhibitors of muscle protein synthesis, and both contractile and non-contractile proteins are affected by acute and chronic alcohol dosage. Muscle RNA is also reduced by mechanisms involving increased RNase activities. In general, muscle protease activities are either reduced or unaltered, although markers of muscle membrane damage are increased which may be related to injury by reactive oxygen species. This supposition is supported by the observation that in the UK, alpha-tocopherol status is poor in myopathic alcoholics. Reduced alpha-tocopherol may pre-dispose the muscle to metabolic injury. However, experimental alpha-tocopherol supplementation is ineffective in preventing ethanol-induced lesions in muscle as defined by reduced rates of protein synthesis and in Spanish alcoholics with myopathy, there is no evidence of impaired alpha-tocopherol status. In conclusion, by a complex series of mechanisms, alcohol adversely affects skeletal muscle. In addition to the mechanical changes to muscle, there are important metabolic consequences, by virtue of the fact that skeletal muscle is 40% of body mass and an important contributor to whole-body protein turnover.

Intraoperative monitoring during surgery for acoustic neuroma: benefits of an extratympanic intrameatal electrode

OBJECTIVES

To assess the utility of an extratympanic intrameatal electrode for intraoperative monitoring during acoustic neuroma and other cerebellopontine angle tumour surgery and to define the neurophysiological and surgical factors which influence hearing preservation.

METHODS

Twenty two patients, 18 with acoustic neuromas and four with other cerebellopontine angle tumours, underwent intraoperative monitoring during tumour excision. The extratympanic intrameatal electrode (IME) was used to record the electrocochleogram (ECoG) and surface electrodes to record the brainstem auditory evoked response (ABR).

RESULTS

The compound action potential (CAP) of the ECoG was two and a half times greater in amplitude than wave I of the ABR and was easily monitored. Virtually instant information was available as minimal averaging was required. Continuous monitoring was possible from the commencement of anaesthesia to skin closure. The IME was easy to place, non-invasive, and did not interfere with the operative field. Operative procedures which affected CAP or wave V latency or amplitude were drilling around the internal auditory meatus, tumour dissection, nerve section, and brainstem and cerebellar retraction. Hearing was achieved in 59% of patients.

CONCLUSIONS

The IME had significant benefits in comparison with other methods of monitoring. The technique provided information beneficial to preservation of hearing.

Chronic inflammatory demyelinating polyneuropathy : clinical, electrophysiological and morphological study

Twelve patients (M:F 9:3) who fulfilled diagnostic criteria of chronic inflammatory demyelinating polyneuropathy (CIDP) were seen at NIMHANS over a period of three years (1987-1990). Their ages ranged from 20 yrs to 71 yrs and the mean duration of symptoms was 30 months (range 3 months to 6 yrs). Symptoms at the onset were dependent on the duration of disease. These included paraesthesia (7), weakness (4) and ataxia in lower limbs (1). Salient features on examintion were: distal weakness (10), proximal weakness (6), impaired touch and pain (12), impaired joint position and vibration sense (6), distal areflexia (12), bilateral impaired hearing (2) and thickened nerves (4). Electrophysiological evidence of demyelination was present in all and albumino cytological dissociation in CSF was noted in 55 of the patients. Sural nerve biopsy revealed significant loss of myelinated fibres in all the five patients studied. Increase in endo and perineural collagen, remyelination and schwann cell proliferation were also seen. Inflammatory infiltrates were conspicuously absent. Steroids were given in 10 patients. The therapeutic response was good in 5 and moderate in 5. Two patients had remitting relapsing course. Response to steroids could not be predicted on the basis of clinical or laboratory features. The recent diagnostic criteria and their therapeutic relevance are discussed.