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Thrombotic thrombocytopenic purpura (TTP) is a systemic disease characterised by the presence of microvascular thrombi resulting from endothelial injury and platelet activation. Vascular occlusion leads to the clinical manifestations of ischaemicorgan damage, microangiopathic haemolytic anaemia and thrombocytopenia. Pancreatitis has rarely been described in association with TTP and has not been reported with TTP in pregnancy. We describe a case of pancreatic necrosis due to TTP which presented in the third trimester of pregnancy and we review the literature relating to this rare complication.

Background.—Appendices removed from patients with suspected appendicitis often appear normal on histologic examination. Objective.—To study appendix specimens for the expression of inflammatory markers as an indicator of presence of an inflammatory response in this subgroup of patients. Methods.—Cyclooxygenase 1 and 2, prostaglandin E2, inducible nitric oxide synthase, and major histocompatibility complex class II were investigated by immunofluorohistochemistry using confocal laser microscopy in 15 acutely inflamed appendix specimens, 39 histologically classified “normal” appendices, and 11 negative control specimens. Results.—Strong expressions of all the inflammatory mediators were found in the mucosa of inflamed appendices, in approximately 50% of histologically normal appendices from patients with a clinical diagnosis of appendicitis, and in none of the normal control specimens. Conclusion.—This study confirms the existence of a subgroup of appendicitis within the so-called histologically normal appendices in which evidence of an inflammatory pathologic condition is only obvious at a molecular level. The initiating signal for this and all other forms of clinical appendicitis still remains elusive.

Hirschsprung's disease (HD) is characterised by the absence of ganglion cells and the presence of hypertrophic nerve trunks in the distal bowel. It has been suggested that aganglionosis may be caused by failure of differentiation as a result of microenvironmental change after neuronal migration has occurred. Recently, it was reported that cell-adhesion molecules (CAMs) and fibroblast growth factors (FGFs) stimulate neurite outgrowth through activation of FGF receptors (FGFRs) in neurons. The aim of this study was to investigate the expression of CAMs FGFs, and FGFRs in ganglionic (NG) and aganglionic (AG) segments of HD in order to understand the role of CAM-FGF signalling in the pathogenesis of HD. Specimens from NG and AG segments of bowel from 11 patients with HD were obtained at the time of definitive pull-through operation, snap-frozen in OCT compound, and stored at -70 degrees C. Aganglionosis was confirmed by Haematoxylin and eosin staining and acetylcholinesterase histochemistry; 8-micron cryosections were immunostained using the standard streptavidinbiotin-immunoperoxidase method. The following antibodies were used as the first antibody; FGF2 and FGF7 for FGFs, FGFR1 and FGFR2 for FGFRs, NCAM, L1CAM, and N-cadherin for CAMs. FGF2, FGF7, and FGFR2 were expressed in neuronal tissue of NG segments as well as in hypertrophic nerves of AG segments. There was a lack of FGFRI expression in neuronal tissue of both NG and AG bowel. Immunoreactivity with all three CAMs was detected in ganglion cells in NG bowel and in hypertrophic nerve trunks in AG bowel. In contrast the numbers of CAM-positive nerve fibres in muscle layers were markedly decreased in AG bowel compared to NG bowel. The markedly decreased expression of CAMs on nerve fibres within the muscle of AG bowel suggests that CAM-FGF signalling is altered in HD, resulting in failure of enteric neuroblast migration.

The etiology of hypertrophic pyloric stenosis (HPS) is not known. We made an immunocytochemical examination of pyloric muscle from 18 patients with HPS and 10 controls using specific monoclonal antibodies to neural cell adhesion molecule (NCAM) as well as neurofilament protein and NADPH-diaphorase histochemistry. In HPS, bundles of hypertrophic muscle fibers expanded the circular muscle layer. The longitudinal muscle also appeared hypertrophic but to a less marked degree. The most striking difference between HPS and the control tissues was that NCAM, NADPH-diaphorase, and neurofilament protein immunoreactive fibers were absent or markedly reduced within the hypertrophied circular and longitudinal musculature. In contrast, NCAM, NADPH-diaphorase, and neurofilament protein immunoreactivity was preserved in the myenteric plexus where nerve fibers and ganglion cells were stained. The lack of expression of NCAM, NADPH-diaphorase, and neurofilament protein on nerve fibers within the circular and longitudinal muscle in patients with pyloric stenosis suggests that the smooth muscle is not innervated in this condition.

The authors studied rectal suction biopsy material in 60 consecutively treated patients suspected of having Hirschsprung's disease (HD) (age range, 3 days to 12 years). According to acetylcholinesterase (AChE) staining, 10 patients had HD, three had neuronal intestinal dysplasia (NID), and 47 were normal. The diagnoses were confirmed by H&E staining of biopsy material and by examination of surgically resected material in the HD and NID cases. The 60 cases were stained with a monoclonal antibody to the nerve growth factor receptor (NGFR) using immunohistochemistry on fresh frozen biopsy tissue. In the 47 normal biopsy specimens, there was a large number of immunoreactive fibers in the lamina propria, and staining of the muscularis mucosae and submucous ganglia. In contrast, there were no immunoreactive fibers in the lamina propria in patients with HD and NID. A striking finding was the strong expression of immunoreactivity on the perineurium of submucosal hypertrophic nerve trunks in cases of HD. The results indicate that NGFR immunoreactivity is similar in specificity and sensitivity to AChE in the diagnosis of HD. Because the technique uses an immunocytochemical rather than a histochemical technique and the results were easier to interpret, NGFR staining may be an important additional technique to diagnose HD.

Intercellular adhesion molecule-1 (ICAM-1) is a glycoprotein that is necessary for the transendothelial migration of leucocytes. This study was undertaken to elucidate the role of ICAM-1 in the pathophysiology of Hirschsprung's disease (HD)-related enterocolitis. Ganglionic and aganglionic portions of bowel from 18 patients with HD who did not have clinical or histological evidence of enterocolitis and 5 patients with HD who developed enterocolitis before or after a pull-through operation were stained using monoclonal antibody against ICAM-1. The bowel specimens obtained from 2 children with imperforate anus at the time of colostomy closure and 3 children at the time of bladder augmentation were similarly stained to act as controls. The ganglionic portion of bowel from patients with HD without enterocolitis and controls showed either no ICAM-I staining or occasional staining of the endothelial lining of submucosal vessels with no staining of the glandular crypt epithelium. In contrast, both ganglionic and aganglionic bowel from patients with enterocolitis complicating HD demonstrated strong ICAM-1 staining in the endothelium of submucosal vessels. Strong expression of ICAM-1 in the glandular crypt epithelium was seen in only 2 patients who had developed enterocolitis before pull-through operations. This study illustrates the importance of endothelial cell activation in the pathogenesis of HD-related enterocolitis.

Enterocolitis remains an important cause of morbidity and mortality in Hirschsprung's disease. The aetiology of enterocolitis is uncertain-ischaemic and bacterial causes and recently, rotavirus infections, have been suggested. Bowel tissue from 12 patients with Hirschsprung's disease who underwent Swenson's operation (five of whom had clinical evidence of enterocolitis) and colon from six controls subjects were examined to investigate possible immunopathological mechanisms associated with the disease. IgA, IgM, and J chain (but not IgG) containing plasma cells were significantly increased in the lamina propria along the entire length of resected bowel in enterocolitis patients, compared with non-enterocolitis patients and controls (p less than 0.01). Luminal secretory component staining of the anganglionic segment of colon from enterocolitis patients was considerably reduced. Lamina propria CD68 positive monocyte/macrophages and CD45RO positive leukocytes were increased in enterocolitis patients compared with non-enterocolitis patients (p less than 0.01). CD57 positive natural killer (NK) cells showed a unique distribution pattern compared with other cell types. Patients with enterocolitis showed a significant increase in CD57 positive NK cells in the lamina propria of ganglionic bowel only (p less than 0.05). NK cell values in ganglionic bowel of non-enterocolitis patients and in aganglionic bowel in all patients were similar to controls. The diversity of altered local immune response seen in this study may reflect a multifactorial microbial aetiology in enterocolitis associated with Hirschsprung's disease.

We examined immunohistochemically the expression and localisation of synapse-associated proteins, syntaxin (SNT) and synaptotagmin (STG) in the entire resected specimens of colon obtained at the time of pull-through operation from 15 patients with Hirschsprung's disease (HD) and 6 age-matched controls. Both antibodies showed a similar pattern of staining. In the normal colon and ganglionic colon from HD, there was strong reactivity in the submucous and myenteric plexuses in addition to staining of nerve fibres in the smooth-muscle layers. In the aganglionic colon, there was an absence or marked decrease in SNT and STG-positive nerve fibres in the smooth-muscle layers and in hypertrophic nerve trunks. Our data indicate that important proteins necessary for the docking of synaptic vesicles at the presynaptic plasma membrane are lost in fibres innervating the smooth muscle of HD and suggest that abnormal neurotransmission may have a role in the maintenance of muscle spasticity.

Since the early 1980s the reports of infection and illness associated withEscherichia coli 0157:H7 have increased dramatically worldwide, and particularly in the USA, Canada and UK. The spectrum of disease varies from asymptomatic carriage to haemorrhagic colitis and haemolytic uraemic syndrome (HUS). This infection is new to Ireland, and we report on 2 cases of isolation which outline the presentation of this organism with haemorrhagic colitis and HUS.

The expression of nerve growth factor receptor in colon from 20 patients with Hirshsprung's disease and 10 controls was studied immunohistochemically. The myenteric and submucous plexuses in the ganglionic bowel and hypertrophic nerve trunks in the aganglionic bowel displayed strong expression of nerve growth factor receptor. The most important finding was the identical localisation of nerve growth factor receptor immunoreactivity on the perineurium of both hypertrophic nerve trunks in Hirshsprung's diseases, and of normal extrinsic nerves, seen as a thick ring surrounding the nerve trunks. This suggests that the hypertrophic nerve trunks are of extrinsic origin and that nerve growth factor receptor plays a role in their development and maintenance.

Hypertrophic nerves have long been considered a histopathologic feature of the aganglionic segment in Hirschsprung disease, but they remain incompletely explained. The purpose of this study was to define the nature and diagnostic importance of hypertrophic nerves in Hirschsprung disease and to clarify their relation to nearby smaller nerve fibers.We used an immunoperoxidase staining technique to compare the distribution of 2 nerve markers-erythrocyte-type glucose transporter (GLUT-1), a marker of perineurium, and nerve growth factor receptor, a marker of both nerve fibers and perineurium-in aganglionic tissue (12 resected specimens and 4 rectal biopsies) and control tissue (6 autopsy specimens and 17 rectal biopsies) of children.In control ganglionic tissue, the myenteric and submucosal areas contained only occasional GLUT-1-positive nerves (usually less than 50 microm in diameter), but extramural extrinsic (serosal) nerves were invariably positive for GLUT-1. In aganglionic tissue, GLUT-1-positive nerves in the myenteric and submucosal areas were frequent and included both large (50-150 microm) and small (50 microm) diameter nerves. Nerve growth factor receptor-positive fibers were frequent in all layers of all tissue studied. In aganglionic bowel, a distinct perineurium could be identified in the largest nerves, but nerve growth factor receptor had poor discrimination for small perineurium-sheathed nerves.Most nerves, of both large and small diameter, in the myenteric and submucosal plexus of aganglionic bowel are GLUT-1 positive. Serosal extrinsic nerves stain identically, supporting the interpretation that the mural nerves are of extrinsic origin. Mural GLUT-1-positive nerves, when they are multiple and especially when they are greater than 50 microm in diameter (a figure which may be used as a threshold for hypertrophic nerves), are suggestive of Hirschsprung disease.

PUBLISHED, BACKGROUND: There is concern that the incidence of non-Hodgkin's lymphoma (NHL) will rise with increasing use of immunosuppressive therapy. AIMS: Our aim was to determine the risk of NHL in a large cohort of patients with inflammatory bowel disease (IBD), and to study the association between IBD, NHL, and immunosuppressive therapy. METHODS: We studied 782 IBD patients (238 of whom received immunosuppressive therapy) who attended our medical centre between 1990 and 1999 (median follow up 8.0 years). Standardised incidence ratios (SIRs) and 95% confidence intervals (CI) were calculated. Expected cases were derived from 1995 age and sex specific incidence rates recorded by the National Cancer Registry of Ireland. RESULTS: There were four cases of NHL in our IBD cohort (SIR 31.2; 95% CI 2.0-85; p=0.0001), all of whom had received immunosuppressive therapy: azathioprine (n=2), methotrexate (n=1), and methotrexate and cyclosporin (n=1). Our immunosuppressive group had a significantly (59 times) higher risk of NHL compared with that expected in the general population (p=0.0001). Three cases were intestinal NHL and one was mesenteric. Mean age at NHL diagnosis was 49 years, mean duration of IBD at the time of NHL diagnosis was 3.1 years, and mean duration between initiation of immunosuppressive therapy and diagnosis of NHL was 20 months. CONCLUSIONS: Although underlying IBD may be a causal factor in the development of intestinal NHL, our experience suggests that immunosuppressive drugs can significantly increase the risk of NHL in IBD. This must be weighed against the improved quality of life and clinical benefit immunosuppressive therapy provides for IBD patients.

To examine the gastrointestinal (GI) immune system in rheumatoid arthritis (RA) for evidence of activation.Duodenal biopsies from 25 patients with RA were obtained by endoscopy. Single cell suspensions from the epithelial layer and lamina propria were prepared. Flow cytometry was used to examine the expression of CD4, CD8, T cell receptor-gammadelta (TCR-gammadelta), TCR-alphabeta, HLA-DR, CD44, and interleukin 2 receptor on gut T lymphocytes. Fifteen disease control (DC) individuals and 6 patients with osteoarthritis (OA) taking longterm nonsteroidal antiinflammatory drug (NSAID) therapy were also investigated. Peripheral blood T lymphocytes from all individuals were examined for the expression of these surface molecules.HLA-DR expression was significantly increased on intraepithelial lymphocytes (IEL) and enterocytes from patients with RA (n = 13) compared with the 2 control groups (p0.01). Immunohistochemistry also revealed increased expression of HLA-DR on enterocytes from patients with RA. RA IEL (n = 6) expressed significantly higher levels of CD44 (p0.02). In the lamina propria, a small but significant gammadelta T lymphocyte population (mean 5.5%, range 2-12%) was detected in rheumatoid factor positive RA patients (n = 8) compared with RF negative RA patients (n = 8, mean 2%, range 0.4-6%; p0.01) and the disease control group (n = 15, mean 2%, range 0.5-5%; p0.01). None of these changes were detectable in peripheral blood lymphocytes from patients with RA.This study demonstrates evidence of activation of specific components of the GI immune system in RA. Peripheral blood T lymphocytes from patients with RA did not show increased expression of activation markers, suggesting that changes in the RA GI tract are not systemic but localized. Moreover, these changes appear to be independent of NSAID therapy.

Wilms' tumor (WT) usually has a good outcome, although a poor prognosis is often related to more advanced stages and anaplastic features. Apoptosis occurs with variable frequency in malignant tumors, and may have a role in reducing their growth rate. The bcl-2 proto-oncogene inhibits apoptosis, and the consequent increase in the number of cells may play a role in the development of tumors. The aim of this study was to analyze the role of apoptosis and bcl-2 expression in WT. Twenty-six resected WT specimens were studied; 12 patients had stage I tumor, 4 stage II, 5 stage III, 3 stage IV, and 2 stage V. Twenty-three tumors were classified as favorable histology (FH) and 3 as unfavorable (UH). The mean follow-up was 34 months; 22 patients were alive and 4 were dead (2 with FH: 1 stage III and 1 stage IV, and 2 with UH stages 4). Apoptosis was detected by the in-situ end-labelling technique; bcl-2 expression was detected by immunohistochemistry. An apoptotic index (AI) was calculated as the ratio of apoptotic to normal cells in each specimen. The AI was lower in higher tumor stages, with a significant difference between stages I and IV (P < 0.05). In cases with UH, Al was lower than in tumors with FH (P < 0.01). The AI was also lower in patients who died than in those who survived (P < 0.01). In all specimens no correlation between AI and bcl-2 expression was observed. Progression to advanced stages of WT and a poor prognosis f anaplastic tumors may be linked with disruption of the mechanisms that control apoptosis. Bcl-2 does not play a role as a regulator of apoptosis in WT, other oncogenes and tumor-suppression genes may be more involved in inhibiting apoptosis in WT.

BACKGROUNDNitric oxide is the most important transmitter in non-adrenergic non-cholinergic nerves in the human gastrointestinal tract. Impaired nitrergic innervation has been described in Hirschsprung’s disease, hypertrophic pyloric stenosis, and intestinal neuronal dysplasia (IND). Recent findings indicate that hyperganglionosis, one of the major criteria of IND, is age dependent. However, information is scanty regarding the neurone density in normal human bowel in the paediatric age group.AIMSTo determine neurone density, morphology, and nitric oxide synthase distribution of the normal myenteric plexus at different ages during infancy and childhood.METHODSSpecimens were obtained from small bowel and colon in 20 children, aged one day to 15 years, at postmortem examination. Whole mount preparations were made of the myenteric plexus, which were subsequently stained using NADPH diaphorase histochemistry (identical to nitric oxide synthase) and cuprolinic blue (a general neuronal marker). The morphology of the myenteric plexus was described and the neurone density estimated.RESULTSThe myenteric plexus meshwork becomes less dense during the first years of life. The density of ganglion cells in the myenteric plexus decreases significantly with age during the first three to four years of life. The NADPH diaphorase positive (nitrergic) subpopulation represents about 34% of all neurones in the myenteric plexus.CONCLUSIONSThe notable decrease in neurone density in the myenteric plexus during the first years of life indicates that development is still an ongoing process in the postnatal enteric nervous system. Applied to the clinical situation, this implies that interpretation of enteric nervous system pathology is dependent on the age of the patient.

Polytetrafluoroethylene (PTFE) paste has been used for over 30 years to treat urinary incontinence and for 14 years to treat vesicoureteral reflux with little reported morbidity. Some investigators have been concerned by the use of PTFE as the implanted substance, because migration of PTFE particles from the site of injection in the periurethral and periureteral regions to the lungs and brain has been reported in animal studies. We injected PTFE paste intravascularly in dogs in order to investigate its effect on brain parenchyma.A total of 12 mongrel dogs, weighing 11.5-17.5 kg, were divided into four groups. Group 1 (n = 3): injection of 0.5 ml of PTFE paste suspended in 50 ml of saline into a peripheral vein once a week for 4 weeks. Group 2 (n = 3): injection of 50 ml of saline into a peripheral vein once a week for 4 weeks as controls. Group 3 (n = 3): one injection of 0.1 ml of PTFE paste suspended in 20 ml of saline into the right carotid artery. Group 4 (n = 3): one injection of 20 ml of saline into the right carotid artery as controls. After an interval of 6 months, all animals were sacrificed and the lungs and brain removed. Brain from 1 animal in each group was dissolved in sodium hypochlorite solution, the resulting organ suspension was centrifuged, and the smear preparations of the precipitate examined by polarized light microscopy, scanning electron microscopy, and X-ray microanalysis. Brains from 2 animals in each group were fixed in formalin solutions, 6-micrometer sections were cut and stained with haematoxylin and eosin, Cajal stain for Purkinje fibre, and Luxol fast blue stain for myelin, and glial fibrillary acidic protein immunohistochemistry was carried for astrocytes using monoclonal mouse anti-GFAP (glial fibrillary acidic protein) at a dilution of 1:50 with an avidin-biotin-peroxidase complex method.PTFE particles were seen in the cerebral vessels in only those animals who had PTFE injected into the right carotid artery. The haematoxylin and eosin staining showed PTFE particles in vessels with focal foreign-body reaction, but no infarction. Luxol fast blue staining showed no demyelination around vessels containing the particles and the parenchyma. Cajal staining demonstrated no abnormality of nerve fibres, and there was no astrocytosis using GFAP immunohistochemical staining.Our findings indicate that following intravenous injection, there was no evidence of migration of PTFE to the brain. Small quantities of PTFE injected into the carotid arteries were associated with local foreign-body reaction, but no brain parenchymal tissue damage was found.

Mucormycosis is an uncommon severe life-threatening fungal infection in the immunocompromised host caused by fungi belonging to the order Mucorales, most commonly Rhizopus arrhizus (R. oryzae). We report a patient who developed a severe right atrial catheter exit site infection with Absidia corymbifera. The catheter was removed and necrotic tissue debrided. With liposomal amphotericin B and G-CSF, the infection subsided. He remains well 8 months later.

Since the early 1980s the reports of infection and illness associated with Escherichia coli O157:H7 have increased dramatically worldwide, and particularly in the USA, Canada and UK. The spectrum of disease varies from asymptomatic carriage to haemorrhagic colitis and haemolytic uraemic syndrome (HUS). This infection is new to Ireland, and we report on 2 cases of isolation which outline the presentation of this organism with haemorrhagic colitis and HUS.

Malignant lymphoma of the testis involves the adjacent epididymis in approximately 60% of cases, but isolated epididymal lymphoma is rare.The file of a 34-year-old man was reviewed, and the biopsy material was studied by conventional morphology, immunohistochemistry, and polymerase chain reaction.The patient presented with painless bilateral epididymal enlargement. Sequential bilateral epididymal biopsies revealed follicular lymphoproliferation with minimal involvement of one testis. Immunoglobulin M antibodies to the Coxsackie B4 virus were increased, and the lesions were interpreted as an atypical reactive process. Chemotherapy was not pursued. Four years after presentation, there was no evidence of local disease, but a 3-cm lesion involving the skin of the forehead developed. An excision biopsy revealed a large cell follicular lymphoma with features resembling the epididymal lesion. Analysis by polymerase chain reaction revealed a t(14-18) translocation in skin and epididymal lesions confirming that the epididymal lesions were also lymphomatous. Staging revealed no other site of disease. To date, the patient, who was treated with methotrexate chemotherapy, remains well 28 months after treatment.Most lymphomas of the testis and epididymis occur in older men, have an intermediate or high grade, diffuse histology, disseminate early, and follow an aggressive clinical course. In contrast, this case is similar to the occasional reports of pseudolymphoma and follicular lymphoma that occur in younger men, are confined largely to the testis and epididymis, and have a good prognosis.

Antibodies to forms of muscle actin have been developed that are highly specific for tissue of myogenic origin and for which false-positive reactions are seldom reported. We studied 23 cases of B-cell malignant lymphoma by immunohistochemistry using monoclonal antiactin antibodies of two different specificities. Eight of the 23 cases were positive with an antibody against smooth-muscle actin that had been produced as ascitic fluid. Reactivity was abolished by the use of antibody from the same clone (1A4) but produced as a tissue culture supernatant. Nine of 23 cases were positive with an antibody against muscle actin (clone HHF35) produced as ascitic fluid. An antibody from the same clone (HHF35), but produced as a tissue culture supernatant, gave weak staining of both lymphoid cells and connective tissue background. Lymphoma staining by both HHF35 antibodies (and background staining) was abolished by the addition of ethylenediaminetetraacetic acid (EDTA) to the antibody. (EDTA is reported to eliminate nonspecific protein binding.) Each ascitic fluid-derived antibody stained the lymphomas in an apparently specific manner. There was intense granular deposition of reaction product localized to specific portions of the cell (plasma membrane or diffuse cytoplasmic staining and, in two signet ring cell lymphomas, globular staining of intracytoplasmic inclusions), and there was substantial concordance of the staining of the two antibodies. This finding of false-positive reactivity by two different antiactin monoclonal antibodies, both prepared as ascitic fluid, supplements recent reports of a similar phenomenon with ascitic fluid preparations of the antimelanoma monoclonal antibody HMB45.(ABSTRACT TRUNCATED AT 250 WORDS)

We studied the internal anal sphincter (IAS) muscle from 10 patients with achalasia and five normal controls using histochemical staining for NADPH-diaphorase and acetylcholinesterase (AChE). Normal control IAS muscle contained occasional AChE-positive nerve fibers, whereas IAS achalasia specimens demonstrated prominent AChE-positive nerve fibers in muscle layers. NADPH-diaphorase activity was strongly expressed in nerves in the normal IAS muscle but was absent or scanty in the muscle of patients with IAS achalasia. Our findings of increased AChE-positive nerves and the absence of NADPH-diaphorase activity taken in conjunction with reports of abnormal peptidergic innervation indicate that complex neural abnormalities occur in IAS achalasia. The primary event remains obscure, but it is possible that a single defect, such as nitrergic nerve depletion, may lead to compensatory changes in the other nerve fibers.

When tissue samples are evaluated for the presence of Hirschsprung's disease, results of acetylcholinesterase staining are usually more informative than findings from the routine hematoxylin-eosin method. The standard technique for staining acetylcholinesterase takes 2 hours to perform and is based on the enzyme histochemical method of Karnovsky and Roots, with a subsequent visualization step as described by Hanker and colleagues. We modified the technique by the introduction of supplemental oxidation, which accelerated the staining time to less than 10 minutes. When evaluated in 10 patients with Hirschsprung's disease and in seven control patients with normal colons, the rapid technique gave identical staining of nerves and ganglion cells to that of the standard method. Increased visualization of endogenous peroxidase-containing histiocytes occurred, but it was not a diagnostic problem. The technique is sufficiently rapid to be used in conjunction with routine frozen sections to assist in the diagnosis and in selecting the optimal level of resection at the time of definitive surgery.

Non-Hodgkin's lymphoma is the commonest secondary cancer following bone marrow transplantation (BMT). We report the case of a 42-year-old man who developed a laryngeal high-grade B-cell lymphoma 5 years following a matched T depleted BMT for CML. Polymerase chain reaction (PCR) analysis using the microsatellite marker Cyp 19 demonstrated the donor origin of involved tissue. Epstein-Barr virus (EBV) genomic sequences were identified by PCR. Although EBV related B-cell lymphoproliferative disorders (BLPD) post BMT are difficult to treat, there was a complete remission in this patient following three courses of chemotherapy (CHOP) administered with G-CSF. This case of late-onset BLPD appears clinically distinct from the well-defined, aggressive, early post-transplant BLPD.

Abstract 5102 Tumour classification defines clinically distinctive, non-overlapping disease entities that serve the basis for future investigation and therapeutic management. The World Health Organization committee for classification of haematological malignancies is truly one of the first worldwide group to provide a consensus approach encompassing morphology, immunophenotyping, genetic and clinical features. However, there are limitations. Not all diseases fit into specific categories. Attention to unique clinical presentations facilitates our continued education. We report a blastic variant of an extramedullary plasmacytoma. A fit 61 year old Caucasian man presented with a progressive neck and right upper limb (RUL) pain. No other relevant past medical or family history. Examination revealed a sensory neuropathy involving the 7th cervical dermatome. MRI cervical spine revealed a 5cm right paravertebral mass extending from C5-T1, surrounding the right vertebral artery and the roots and trunks of the right brachial plexus. It extended into the right neural foramina at the C5-C6, C6-C7 and C7-T1 levels with more minimal invasion at the C4-C5 level. Over a two week period he complained of increasing RUL pain, a right Horner's syndrome and weakness of the small muscles of his hand. An excision biopsy of the mass was performed and staging investigations were completed including CT body, lumbar puncture, bone marrow aspirate/biopsy, serum and urine protein electrophoresis. A PET/CT showed the right sided paraspinal nodal mass with low to moderate metabolic activity. A diffuse, monotonous population of medium size cells with average nuclear: cytoplasm ratios, blastic chromatin, round nuclei and smooth contours surrounding a relatively unremarkable reactive lymph node. Mitoses are readily apparent, along with 'starry sky' appearance imparted by numerous tangible-body macrophages within the infiltrate. An extensive immunohistochemical panel were performed. The cells of interest express CD45, Cd38, vs38, CD138, MUM1, CD4, CD15, p53, weak CD19 and lambda light chain. The proliferation rate by Ki-67 is high approximately 60%. The overall phenotype was consistent with plasma cell differentiation but the mitotic rate and morphological rate does not fit well. An initial response to definitive radiotherapy (40Gy/20fr) was swiftly followed 6 weeks later with a profound C5 radiculopathy. MRI imaging confirmed an extra-axial lesion, lying partially within the radiation port. The patient is now receiving salvage chemotherapy. The behaviour of this lesion both under the microscope at the bench and the bedside is at odds with that predicated for a plasmacytoma, highlighting the critical importance of interplay between different medical disciplines. While blastic variants have been described for many haematological malignancies, it has not been previously reported in this situation. Disclosures: No relevant conflicts of interest to declare.

A 64-year-old woman was referred with a short history of abdominal pain, anorexia and weight loss. Investigations revealed a probable enteropathy associated T-cell lymphoma (EATL). Further investigations revealed evidence of what appeared to be a myocardial infarction. After going through laparoscopy to obtain diagnostic tissue, the patient developed cardiogenic shock which proved refractory to medical therapy. Postmortem examination revealed diffuse abdominal lymphoma consistent with EATL. Surprisingly, there was extensive infiltration of the myocardium. This report demonstrates an unusual pathology resulting from EATL and discusses the limited evidence relating to cardiac involvement of this disease.

Atheroembolism, although not infrequent at autopsy, is seldom identified in life, when it may present as a multisystem disease involving lower limbs, kidney, and gastrointestinal (GI) tract. Diagnosis of isolated GI involvement usually requires examination of surgically resected tissue, because recognition by endoscopic GI biopsy is exceptional. We diagnosed colorectal atheroembolism by biopsy in four patients. All were elderly (68-80 years old) and had generalized atheroma, including aortic aneurysms. Three patients had sudden onset of frank rectal bleeding with clots or bloody diarrhea, lower abdominal discomfort, and tenderness. Biopsy revealed atheroemboli in a rectal ischemic ulcer and in colorectal adenomatous polyps. In all three, disease resolved on conservative management and did not recur during the period of follow-up. In the fourth patient, asymptomatic atheroembolism was identified in an adenomatous polyp at the splenic flexure. Extraintestinal disease attributable to atheroembolism was not present in any of the patients. Atheroembolism with manifestations confined to the colon may sometimes be diagnosed by biopsy, appears to be more frequent than currently recognized, and may present a diagnostic challenge as a self-limited episode of rectal bleeding.

Details of injuries and exposures to body fluids while handling tissue that were sustained by 36 pathologists (nine residents and 27 staff pathologists) were ascertained by retrospective questionnaire. In the preceding year 56% (20/36) had sustained a cut or needlestick injury. A total of 72 individual injuries occurred and corresponded to one injury for every 2629 surgical specimens handled and for every 37 autopsies performed. Residents reported a five-fold excess in injuries compared with staff pathologists. The lesions described predominantly (67%) involved the oppositional area consisting of the distal thumb, index, and middle fingers of the nondominant hand; during dissection, when opposed to hold or retract tissue, these digits form a surface that is directly exposed to the cutting edge, and injury to this area may be termed dissector's digital injury. Injuries to other areas of the nondominant hand were much less numerous and the dominant hand was rarely injured. Splashes to the face and eyes and glove punctures were frequent. These injury and exposure rates are probably broadly representative of practice in areas of low acquired immunodeficiency syndrome prevalence and may be improved on with increasing concern about human immunodeficiency virus infection. It is likely, however, that development of comfortable protective devices, based on knowledge of the pattern and circumstances of injury, will be necessary to eliminate these occupational hazards.

Persistent polyclonal B lymphocytosis (PPBL), a rare benign lymphoproliferative disorder, occurred in a 25 year old woman. The lymphocytes showed the phenotype cIgM+, FMC7+, CD19+, CD20+, which was similar to that seen in Waldenstrom's macroglobinaemia, but the proliferation was repeatedly shown to be polyclonal both immunologically and by immunoglobulin gene rearrangement studies. Eleven years after presentation the patient developed a malignant pulmonary blastoma, a rare pulmonary tumour of combined epithelial and mesenchymal origin. The failure to develop a lymphoid malignancy over 11 years together with immunological and genetic evidence of polyclonality confirms that PPBL is a benign lymphoproliferative disorder. The subsequent occurrence of a nonhaemopoietic malignancy suggests that benign lymphoid proliferations, like their malignant counterparts, may predispose to the development of neoplasia. A role for Epstein-Barr virus in the pathogenesis of one or both of these rare conditions is suggested by the finding of raised Epstein-Barr viral capsid antigen titres.

We describe the results of 43 bronchoscopic examinations carried out on 35 patients who were HIV positive. Of these, 13 were intravenous drug abusers, 13 were homosexual or bisexual, six were haemophiliacs, two were homosexual intravenous drug abusers and one was a heterosexual contact of a drug abuser. All underwent investigation because of respiratory symptoms. Aetiological diagnosis could not be made from physical examination, x-ray or routine laboratory tests but, was usually made using bronchoscopy and its associated investigations. Using these techniques, Pneumocystis carinii pneumonia was the commonest diagnosis (19 cases) followed by bacterial infection. Mycobacterial infection accounted for two cases and non-specific interstitial pneumonitis accounted for three. Kaposi's sarcoma was found in one instance and eight investigations were non-diagnostic.

A longitudinal study with follow up to the end of 1989 was carried out on 23 patients with AIDS who had attended St. James's Hospital, Dublin, by the end of 1987. Until then only 33 cases of AIDS had been reported in Ireland. The patients, all of whom had antibodies to human immunodeficiency virus (HIV), were predominantly male, young (mean age 31.3 years) and belonged about equally to three major risk groups: homosexuals, intravenous drug abusers (IVDA) and haemophiliacs. AIDS was diagnosed because of oesophageal candidiasis (8 cases), Kaposi's sarcoma (4), mycobacterial infection (4), pneumocystis carinii pneumonia (3), toxoplasmosis (2) or encephalopathy (2). Malignant lymphoma and a variety of infections occurred in the course of illness, and neurological involvement developed in 11 patients (48%). Mortality following diagnosis of AIDS was 39% at one year and 64% after two years. Autopsy in 10 of the 16 deaths contributed much to defining the extent and nature of the disease. The demographic pattern, risk group status, survival and range of complications were broadly similar to the pattern of AIDS as seen elsewhere in developed countries. However, compared to the profile of disease reported from the United States, oesophageal candidiasis (52%) and Mycobacterium tuberculosis (22%) were more prominent, pneumocystis carinii pneumonia (39%), Kaposi's sarcoma (22%) and Mycobacterium avium intracellulare (13%) were less frequent and cryptococcal infection was not identified. These regional variations in the frequency of the various complications and particularly the prominence of tuberculosis, probably reflect the interaction of the immunocompromised patient with the local environment and may have important diagnostic and therapeutic implications.

A 60 year old woman presented with chest pain. An ECG showed ST depression across the anterior leads and lateral T wave inversion and angiography showed a significant proximal circumflex lesion. After percutaneous intervention to the circumflex artery she had a cardiac arrest and died. Postmortem examination found a stent blocked with a combination of thrombus and a tangle of translucent material. Embolic coronary artery occlusion is well described but this is the first report of embolisation of material arising from the lining of the guiding catheter as the cause.

A 48 year old patient with resistant coeliac disease developed prolonged unexplained pyrexia after surgery for small bowel volvulus. Despite extensive investigations and intensive antibiotic therapy, he deteriorated and died eight weeks postoperatively and significant isolated pulmonary valve endocarditis was discovered at autopsy. This diagnosis should be considered in all critically ill patients with unexplained pyrexia even in the absence of clinical features of endocarditis and transoesophageal echocardiography performed to exclude or confirm this lesion.

Multiple lymphomatous polyposis of the gastrointestinal tract was initially described as mucosal lymphomatous involvement by any of a variety of Hodgkin's or non-Hodgkin's lymphomas that produced a polypoid appearance over long segments of the gastrointestinal tract. We studied four patients in whom histology revealed diffuse small cleaved cell lymphoma (one case), or intermediate lymphocytic lymphoma of diffuse type (one case), or mantle zone pattern (two cases). All four cases are classifiable as centrocytic lymphoma. Cell suspension and immunocytochemical studies demonstrated B-cells of IgMD or M type with light chain restriction (two kappa, two lambda) showing a B1+ HLA Dr+ LN2+ CD5+ CD10+. Although all four patients had a partial response to combination chemotherapy, three of them died within 3 years. Analysis of 24 cases reported since 1971 (including the present cases) suggests that MLP is a distinct clinicopathological entity that results from gastrointestinal involvement by a B-cell centrocytic lymphoma. It is distinct from the recently described clinicopathological forms of centrocytic lymphoma and intermediate lymphocytic lymphoma, which both show extensive peripheral lymphadenopathy and splenomegaly, but it is probably closely related to them. The differences are probably attributable to distinct cell tropism or homing properties rather than to cellular histogenesis or degree of maturation.

Twenty three cases of pseudomembranous colitis (PMC) occurred in three hospitals in 10 months. Retrospective analysis shows that they represented a single epidemic with a readily traceable chain of person-to-person contact within and between hospitals. Most patients had severe pre-existing illness and all had broad spectrum antibiotics, including either ampicillin/amoxycillin, a broad spectrum cephalosporin (particularly cefotaxime), or both. All patients had severe diarrhoea and all responded to vancomycin, but relapse occurred in five. Ten patients eventually died, principally because of underlying disease rather than from PMC. Failure to find fibrin thrombi in blood vessels in biopsies and the scanty distribution of non-invasive bacteria supports the concept of mucosal damage by bacterial toxin, rather than by direct infection, or ischaemia. Although environmental colonisation cannot be excluded, the observed pattern of spread suggests a major role for direct person-to-person crossinfection in the spread of disease in this outbreak.