Underestimated risks of recurrent long-range ash dispersal from northern Pacific Arc volcanoes.

Widespread ash dispersal poses a significant natural hazard to society, particularly in relation to disruption to aviation. Assessing the extent of the threat of far-travelled ash clouds on flight paths is substantially hindered by an incomplete volcanic history and an underestimation of the potential reach of distant eruptive centres. The risk of extensive ash clouds to aviation is thus poorly quantified. New evidence is presented of explosive Late Pleistocene eruptions in the Pacific Arc, currently undocumented in the proximal geological record, which dispersed ash up to 8000 km from source. Twelve microscopic ash deposits or cryptotephra, invisible to the naked eye, discovered within Greenland ice-cores, and ranging in age between 11.1 and 83.7 ka b2k, are compositionally matched to northern Pacific Arc sources including Japan, Kamchatka, Cascades and Alaska. Only two cryptotephra deposits are correlated to known high-magnitude eruptions (Towada-H, Japan, ca 15 ka BP and Mount St Helens Set M, ca 28 ka BP). For the remaining 10 deposits, there is no evidence of age- and compositionally-equivalent eruptive events in regional volcanic stratigraphies. This highlights the inherent problem of under-reporting eruptions and the dangers of underestimating the long-term risk of widespread ash dispersal for trans-Pacific and trans-Atlantic flight routes.

Vasculitis of peripheral nerve and skeletal muscle: clinicopathological correlation and immunopathic mechanisms.

In order to elucidate the pathogenesis of vasculitis in muscle and nerve a clinicopathological study was performed in 23 patients. The patients could be classified into three groups: I multisystem vasculitis (n = 4); II multisystem disease with vasculitis detectable in nerve, muscle, or both (n = 11); and III localised disease with vasculitis in nerve, muscle, or both (n = 8). Ten of 23 patients had vasculitis in both muscle and nerve biopsies; 6 from groups I and II, and 4 from group III indicating that vasculitis confined to muscle and nerve represents a distinct clinicopathological entity. The neuromuscular manifestations in the 23 patients were sensori-motor polyneuropathy (n = 9), mononeuritis multiplex (n = 6), mononeuropathy (n = 3), proximal myopathy (n = 4), and muscle tenderness without weakness (n = 1). Sensori-motor polyneuropathy was found in 8/11 patients from group II, and mononeuritis multiplex in 5/8 patients from group III. Immunotypic analysis, and immunofluorescence patterns indicate that the pathogenesis of vasculitis in muscle and nerve is heterogeneous and suggest that cell mediated and immune complex mechanisms predominate and may be operative in all three patient groups, with an antibody-mediated humoral mechanism in some patients with paraproteinaemic states (group II).

Test and teach. Number seventy-three. Diagnosis: Alexander's disease.

Alexander's disease is a progressive degenerative neurological disorder developing in early childhood which is characterized by accumulation of Rosenthal fibres throughout the cerebral white matter. These fibres are composed of glial fibrillary acidic protein and ubiquinated alpha beta crystallin. The absence of atypia, increased cellularity, mitotic activity or necrosis in biopsy material allows differentiation from neoplasia glial processes. Clinical features suggestive of the diagnosis include progressive mental retardation with an increase in head circumference.

Chromosomal analysis in Ewing sarcoma.

Two cases of Ewing sarcoma were karyotyped by using a fluorodeoxyuridine synchronisation procedure on short term cultures of fresh tumour material. This procedure enables rapid cytogenetic analysis of such material. Both showed relatively simple karyotypes, 48,XX, +2, +7,t(11;22)(q24;q12), ?dup(12)(q21----q24) and 47,XX,i(1q),t(11;22)(q24;q12). These results further support this translocation between chromosomes 11 and 22 as a specific marker for Ewing sarcoma. Cytogenetic studies in such cases are an important adjunct to histological studies and in some cases may contribute to the resolution of the diagnosis.

Adrenal cortical tumors in childhood--clinicopathological features of six cases.

Six cases of adrenal cortical tumors are presented with a discussion of the clinical features and histological findings. Five of the 6 children, aged between 6 mths and 6 yrs, presented with symptoms of hyperadrenalism, 4 with virilization and 1 with Cushingoid features. The remaining infant presented with an asymptomatic abdominal mass. In each case there was a unilateral tumor separated from the residual adrenal gland by a thin fibrous capsule. Surgical resection was the treatment employed and, in the 5 cases with functional tumors, perioperative hydrocortisone was given. None of the children received post-operative chemotherapy or radiotherapy. Bizarre cellular morphology, a high mitotic count and extensive necrosis were all seen in clinically benign disease, demonstrating not only the efficacy of local resection but also the difficulty in applying the usual histological criteria of malignancy to these pediatric adrenal tumors. At follow-up, 5 of the 6 patients are alive with no evidence of recurrent disease. The only death resulted from measles pneumonitis in the 1 child who presented with Cushing's syndrome.

Clinicopathological features of xanthogranulomatous pyelonephritis in infancy.

Xanthogranulomatous pyelonephritis (XGP) is an unusual chronic inflammatory condition which most often affects women in their 5th to 7th decades and is rare in infants. Predisposing factors include infection, calculi and obstructive uropathy. We have reviewed the surgical files of 4 cases seen over a 28 yr period from 1964-91. All of the 3 partial and one total nephrectomy specimens demonstrated typical features of XGP with renal parenchyma effaced by a mixed acute and chronic inflammatory infiltrate which included prominent aggregates of foamy histiocytes containing eosinophilic inclusions. No Michaelis-Gutmann bodies were seen. This study shows the association of XGP with chronic infection, anatomical malformation and reflux in infancy, and raises the possibility of a temporary altered immune response in its pathogenesis.

The spectrum of presentation at autopsy of myocarditis in infancy and childhood.

To characterize the clinicopathological presentation of patients with myocarditis coming to autopsy in childhood, 32 cases of histologically-proven myocarditis were obtained from the files of the Adelaide Children's Hospital. In 16 of the cases (Group A), myocarditis was the only significant finding and death was ascribed to this condition. In the remaining 16 (Group B) myocarditis was found in association with other severe disease processes. Clinical histories of the 2 groups showed sudden death to be a feature in 5 out of 16 cases in Group A, 3 of whom had no prodromal symptoms. Five patients in Group B also suffered sudden death, but this was associated with a variety of causes, including bronchopneumonia, and asphyxia. These cases demonstrate the variability in clinicopathological presentation of myocarditis in infancy and childhood and suggest that myocarditis should always be considered a possible diagnosis at autopsy in the pediatric age group, even in the presence of coincident lethal disease.

Growth and antigenic characteristics of basal cell carcinoma in culture.

Basal cell carcinomas (BCCs) were cultured using an explant method and compared with normal cultured skin. Immunohistochemical staining revealed reduced beta 2 microglobulin uptake by BCCs in frozen section, but normal staining of the tumours in culture. In culture, fibronectin was detected on the cell surface of normal keratinocytes but not on BCCs. The above differences may explain some of the behaviour of BCCs in vivo.

Sudden death in early infancy due to delayed cardiac tamponade complicating central venous line insertion and cardiac catheterization.

Cardiac tamponade is an unusual cause of sudden death in the first weeks of life. We present two cases of cardiac tamponade in the neonatal period that caused death 5 to 6 days following the insertion of intracardiac lines, to draw attention to the possibility of a "delay phenomenon" between the time of the initial procedure and the occurrence of sudden and unexpected death. The presence of blood or clear fluid within the pericardial sac should prompt careful examination of the myocardium for small foci of traumatic damage, particularly when the fluid is under pressure or of large volume. Although the development of circulatory impairment or shock in the days following central line insertion or catheterization raises the possibility of tamponade, it should be noted that sudden death may occur in the absence of any significant antemortem symptoms or signs.

Anomalous coronary arteries arising from the aorta associated with sudden death in infancy and early childhood. An autopsy series.

Anomalous coronary arteries arising from the aorta are a recognized cause of myocardial ischemia and sudden death. Death has been precipitated by exercise in most cases. We present the results of an autopsy study in which sudden and unexpected deaths associated with coronary anomalies were found in three children (less than 2 years of age). In two cases, death was not associated with exercise. In two case, the myocardium was morphologically normal, and in the third case, there was an extensive recent anterior myocardial infarct with a background of established fibrosis. Coronary artery anomalies may be easily overlooked in this age group because of small vessel size and difficulty in dissection; this is particularly so when there are normally placed ostia. One consequence of this is potential for confusion with sudden infant death syndrome.

Mesh-sided cots--yet another potentially dangerous infant sleeping environment.

Two cases of accidental asphyxia involving an 11.5 month old boy and a 3.5 month old boy who each died after being trapped between the elastic mesh side of their cots and the cot mattress are reported. In both cases the original cot mattress has either been replaced or augmented by a less well fitting, thicker mattress. Particular problems that exist with these type of mesh sided cots are the potential for considerable stretching of the side of the cot admitting the relatively larger, poorly supported infant head, with elastic recoil of the mesh holding the head in potentially dangerous positions. To help determine whether accidental asphyxia has occurred, death scene examination in cases of sudden infant death during sleep should include reconstruction of the position of the body in the cot or bed, with careful examination of the structure of the cot/bed.

The Apert syndrome hand: pathologic anatomy and clinical manifestations.

The Apert syndrome hand demonstrates many typical clinical features including syndactyly, symbrachyphalangism, and growth disturbances. This is due to the grossly abnormal anatomy of both the skeletal and soft-tissue structures associated with a progressive disease process. This paper presents a clinical, radiologic, and histologic analysis of the Apert syndrome hand anatomy and correlates it with the clinical manifestations. It also links hand and craniofacial dysplasia to other regions of the skeleton as well as the overall disease process. From our analysis, we conclude that there is a genetic anomaly causing variable and uncoordinated differentiation of the mesenchyme at the time of embryologic separation into its various skeletal components, particularly in the distal limb bud and craniofacial skeleton. This disease process continues postnatally in endochondral bone growth center malformation and malfunction as well as ectopic cartilage ossification in soft tissues. We discuss the role of abnormal musculotendinous anatomy and altered biomechanical forces in relation to these processes.

Leiomyosarcoma of the saphenous vein in a child with 12-year follow-up.

Leiomyosarcomas of the vasculature are exceedingly rare tumors in childhood. The case of a 2-year-old girl who underwent three local excisions with two courses of adjuvant chemotherapy over 3 years for a leiomyosarcoma of a saphenous vein tributary is described. Follow-up over the following 9 years has shown no evidence of further recurrence or metastases suggesting that cure has been achieved. Treatment options are discussed and pertinent literature is reviewed.

Brain tumours in infancy: a clinicopathological study.

To investigate the clinicopathological features of brain tumours occurring in the first year of life, the records of the Department of Histopathology at the Adelaide Children's Hospital were examined for cases where the initial diagnosis of intracranial neoplasm had been made in infancy. Surgical material was available for review from 1972 to 1993 and autopsy cases were reviewed for an additional 12 years from 1962 to 1993. Twenty-four infants with intracranial neoplasms were diagnosed ranging in age from 5 days to 1 year (average = 7 months). There were 23 surgical cases and 1 autopsy case. The male to female ratio was 17:7. Fifty-eight percent of the tumours were located in the supratentorial region. Although the incidence is relatively low, this study demonstrates that a wide range of brain tumours, which differ significantly in both clinical presentation and location from those found in the older child, do occur during the first year of life. The location of the primary tumour may be affected by associated congenital malformations, and metastatic malignancy, although rare, may occur. Antenatal ultrasound examination may be useful in identifying congenital intracranial tumours.

The association of lingual thyroglossal duct remnants with sudden death in infancy.

Two cases of sudden infant death are described in which relatively large posterior lingual midline cysts were demonstrated at autopsy. Death in both patients was attributed to upper airway obstruction due to the cysts, both of which represented thyroglossal duct remnants.

Association of right coronary artery hypoplasia with sudden death in an eleven-year-old child.

Congenital coronary artery abnormalities are a rare but well-documented cause of sudden and unexpected death in the pediatric age group. Most reported cases involve both an aberrant origin and course of the abnormal vessel. A case of unexpected death occurring in an otherwise healthy eleven-year-old boy, who had been previously investigated for sudden collapse, is described. The major finding at autopsy was marked disparity in diameter between the coronary arteries due to diffuse hypoplasia of the right coronary artery. This case demonstrates the importance of meticulous examination of the coronary artery system in cases of sudden death in childhood so that significant reduction in luminal cross section will be adequately documented. The possible role played by this finding in the etiology of sudden death is discussed.

Incidental cardiac rhabdomyomas: a significant finding necessitating additional investigation at the time of autopsy.

Cardiac rhabdomyomas are rare lesions forming part of the tuberous sclerosis complex that may be responsible for sudden death. As well as remaining clinically occult for variable periods of time, they may, along with other manifestations of tuberous sclerosis, be quite difficult to detect clinically and pathologically. A patient is described in whom multiple cardiac rhabdomyomas were an incidental finding at autopsy following fatal potassium fluoride poisoning. Other gross pathological lesions typical of tuberous sclerosis were present but were quite subtle in appearance. Awareness of the association of cardiac rhabdomyomas with tuberous sclerosis is important so that full examination of organ systems for characteristic lesions can be undertaken during the autopsy, and so that fresh and frozen tissue can be obtained at the time of dissection for further investigation.

Cardiac echinococcosis with fatal intracerebral embolism.

A previously well 7 year old boy presented with sudden loss of consciousness and fitting. No evidence of trauma or space occupying lesion was identified. Death occurred the next day due to cerebral infarction caused by embolised fragments from a ruptured left ventricular hydatid cyst that was found at necropsy.

Cranial suture disease in the Apert's syndrome infant.

The histologic findings from sutural specimens remove during early cranial surgery in Apert's syndrome infants have been reviewed. Coronal sutures are uniformly fused histologically in their inferolateral extent, showing a progression to lesser changes at the superior margin. These findings correspond with radiographic changes. The lambdoid sutures occasionally show histologic evidence of fusion, with the same pattern of inferior to superior progression, but a lack of objective radiographic changes.