Guidelines for the use of EEG methodology in the diagnosis of epilepsy. International League Against Epilepsy: commission report. Commission on European Affairs: Subcommission on European Guidelines

The Commission of European Affairs of the International League Against Epilepsy published 'Appropriate Standards for Epilepsy Care Across Europe' which contained recommendations for the use of electroencephalography (EEG) in the diagnosis of epilepsy (Brodie et al. Epilepsia 1997; 38:1245). The need for a more specific basic document of EEG methodology was recognized and the Subcommission on European Affairs was asked to produce more detailed guidelines to be used across Europe recognizing the range of practices in EEG laboratories. There are many general guidelines published on EEG methodology but this document focuses on the diagnosis of epilepsy. Details from previously published guidelines are included in references and in an appendix. These guidelines are not meant to be used as minimal standards but recommendations that can be applied to all EEG laboratories despite variations in equipment.

Acetylcholine receptor delta subunit mutations underlie a fast-channel myasthenic syndrome and arthrogryposis multiplex congenita

Limitation of movement during fetal development may lead to multiple joint contractures in the neonate, termed arthrogryposis multiplex congenita. Neuromuscular disorders are among the many different causes of reduced fetal movement. Many congenital myasthenic syndromes (CMSs) are due to mutations of the adult-specific epsilon subunit of the acetylcholine receptor (AChR), and, thus, functional deficits do not arise until late in gestation. However, an earlier effect on the fetus might be predicted with some defects of other AChR subunits. We studied a child who presented at birth with joint contractures and was subsequently found to have a CMS. Mutational screening revealed heteroallelic mutation within the AChR delta subunit gene, delta 756ins2 and delta E59K. Expression studies demonstrate that delta 756ins2 is a null mutation. By contrast, both fetal and adult AChR containing delta E59K have shorter than normal channel activations that predict fast decay of endplate currents. Thus, delta E59K causes dysfunction of fetal as well as the adult AChR and would explain the presence of joint contractures on the basis of reduced fetal movement. This is the first report of the association of AChR gene mutations with arthrogryposis multiplex congenita. It is probable that mutations that severely disrupt function of fetal AChR will underlie additional cases.

The significance of bilateral EEG abnormalities before and after hemispherectomy in children with unilateral major hemisphere lesions

The rate of seizure relief following hemispherectomy varies between 50 and more than 80%. There has been particular debate concerning the significance of bilateral electroencephalography (EEG) abnormalities in influencing prognosis. This study was set out to determine the frequency of bilateral EEG abnormalities and their relationship to underlying pathology and outcome. We investigated 28 children with unilateral hemisphere lesions, who underwent hemispherectomy. Interictal and ictal EEGs before and after hemispherectomy were reviewed. Post-operative outcome with respect to seizures was noted. Bilateral EEG abnormalities were seen in 75%, but were more common in children with malformations of cortical development than in patients with acquired cerebral lesions, and were found more often in interictal than in ictal records. Post-operative EEG abnormalities were variable and did not consistently predict outcome. Short-term outcome was similar, irrespective of aetiology. With longer term follow-up, only 47% of children with developmental abnormalities were still seizure-free in contrast to 77% of children with acquired abnormalities. Although the incidence of bilateral EEG abnormalities in patients with major unilateral hemisphere lesions is high, these findings alone should not preclude further consideration for hemispherectomy. Our findings emphasise that the aetiology of the lesion plays a major role in determining outcome.

Necrosis in benign salivary gland neoplasms. Not necessarily a sign of malignant transformation

Necrosis that occurs in a salivary gland neoplasm is usually considered to be an ominous sign, suggesting malignant transformation, particularly in lesions that have had no prior manipulation such as fine-needle aspiration. We describe five pleomorphic adenomas and two canalicular adenomas of salivary gland origin that exhibited necrosis, yet were otherwise benign. All lesions displayed a distinctive histopathologic pattern characterized by a narrow rim of viable tumor tissue at the periphery of the neoplasm combined with a diffuse central region that demonstrated apparent ischemic necrosis. No invasion of adjacent normal tissue was identified, and no recurrence or metastasis has been seen with these lesions. Caution should be exercised in the evaluation of salivary gland neoplasms with central necrosis to avoid misdiagnosis of all such lesions as malignant.

Leiomyosarcoma metastatic to the oral region. Report of three cases

Leiomyosarcoma, a malignant lesion of smooth muscle origin, is rare in the oral region. Metastatic leiomyosarcoma may originate from several potential primary sites, and the lung is the most common target tissue for metastatic deposits. This article describes three cases of leiomyosarcoma that were metastatic to the oral cavity and discusses the clinical and histopathologic differential diagnosis.

Carcinoma arising in an odontogenic keratocyst with orbital invasion

A 54-year-old black female presented with proptosis and reduced visual acuity of the left eye. Computerized tomography (CT) revealed tumor involvement of the left cavernous sinus and posterior orbit. The patient had a nineteen year history of a left-sided jaw tumor which recurred despite surgical and radiation therapy. Biopsy demonstrated a parakeratinized odontogenic keratocyst with areas of transformation into an invasive squamous cell carcinoma. Although a parakeratinized odontogenic keratocyst may be locally invasive, to our knowledge, no case of a parakeratinized odontogenic keratocyst involving the orbit or cavernous sinus previously has been reported.

The Noonan syndrome/cherubism association

Noonan syndrome is characterized by short stature, unusual facies, congenital heart disease, chest deformity, mild mental retardation, and cryptorchidism in males. It may be sporadic or inherited as an autosomal dominant trait and occurs between 1 in 1000 and 1 in 2500 live births. Cherubism is a giant cell lesion of the jaws thought to be transmitted as an autosomal dominant trait. It is usually recognized by age 7 years, follows a variable course, and is not known to be related to other genetic disorders. We herein report on four patients with Noonan syndrome, all of whom had cherubism. Two other probable cases are cited in the literature for a total of six known cases.

White sponge nevus. Diagnosis by light microscopic and ultrastructural cytology

The lesions of white sponge nevus, an autosomal dominant abnormality of squamous epithelial differentiation that primarily affects the oral cavity, may be grossly similar to those of other hereditary mucosal syndromes, infections or preneoplastic/neoplastic processes. This differential diagnosis is best resolved in many cases by exfoliative cytology, interpreted in the context of clinical history and physical findings. The following report describes a case of white sponge nevus with typical clinical and cytologic findings, in which the diagnosis was confirmed by ultrastructural cytology. Light microscopic cytology revealed parakeratotic cells and many cells containing dense eosinophilic intracytoplasmic inclusions. Electron micrographs of exfoliated cells demonstrated that these inclusions are composed of disordered aggregates of tonofilaments.

The verruciform xanthoma. A review and report of eight new cases

The verruciform xanthoma (VX) is an uncommon lesion that most often occurs in the oral cavity but occasionally may be seen in other sites. Eight new cases of VX of the oral mucosa are presented. The histologic features are discussed and theories of etiology and pathogenesis are reviewed. The VX appears to be a reactive lesion in which the xanthoma cells arise secondarily to degeneration of cells in the overlying epithelium.

Two cases of X/autosome translocation in females with incontinentia pigmenti

We report two unrelated girls who present some clinical features of severe incontinentia pigmenti (IP), with characteristic skin pigmentation. Both have balanced de novo X/autosome translocations involving band Xp11. The coincidence of the probable de novo expression of an X-linked disorder in these two girls with translocations involving similar breakpoints on the X chromosome suggests that this band may be the site of the IP gene locus.