[Dynamic studies of Langerhans cell histiocytosis cells. Their contribution to the current concept of the disease. Report of a series of 38 cases]

In vitro explantation of 38 fragments of eosinophilic granuloma of bones was attempted. A satisfactory growth was obtained in nearly 90% of cases. This short-term culture maintained the ultrastructural characteristics and, to a lesser extent, the cytochemical features of the Langerhans cells, confirming the Langerhans cell origin of this cell proliferation. In addition, this procedure was able to demonstrate an immunodependent erythrophagocytosis (3/3) and a preferential fixation of labelled precursors (Glycerol, choline of lipid metabolism as well as labelled dopamine (2/2). All attempts to obtain a permanent cell line and graft to nude mice (even irradiated) failed. Under the in vitro conditions, the Langerhans cells do not divide up but can be readily identified up to 2 or 3 weeks. The contrast between the evident in vivo proliferation and the in vitro quiescent state suggests that some undetermined growth-factors targeted to the Langerhans cell system are missing in our commonly used culture media. The in vitro culture procedure could be of some help to their identification.

Malignant histiocytosis. Histologic, cytochemical, chromosomal, and molecular data with a nosologic discussion

Although myelomonoblastic leukemia is thought to originate from a malignant transformation of the stem cell of the mononuclear phagocyte system, malignant histiocytosis (MH) is classically assumed to represent a malignant change of the terminal and fixed elements of this system. Indeed, MH is characterized by the proliferation of large, clear, pleomorphic, "histiocytic-like" HLADR and CD30+ cells resulting in a nodal and extranodal disseminated neoplasm affecting preferentially and severely children and young adults. Although there is broad agreement on the clinicopathologic presentation of this condition, there is currently quite a controversy over the T-lymphoid or histiocytic origin of the proliferative cells that results in a nosologic discussion between the anaplastic large cell lymphoma (ALCL) advocates and the MH supporters. This article has dealt mainly with this nosologic discussion and with the contributions provided by the investigations performed on MH permanent cell lines. These in vitro studies have demonstrated that the proliferation is characterized by a unique chromosomal abnormality, the 5q35bp usually associated with a t(2;5) translocation generating a fusion gene NPM/ALK and the subsequent translation of p80 protein. Although it is known that no single chromosomal abnormality is strictly restricted to a cell lineage, this 5q35bp and associated translocations seem today to represent the hallmark for this condition. In view of these chromosomal aberrations, the CD30+ ALCLs represent a heterogeneous group because 15% to 50% express the NPM/ALK fusion gene. In addition, these in vitro investigations have shown that 5q35bp proliferative cells are glass-adherent, can develop an immunodependent phagocytosis, and are able to reduce NBT and produce TNF-alpha. More significantly, they express constitutively the c-fms (the receptor of the macrophage growth factor) and, under TPA stimulation, are able to modulate the expression of this receptor and its ligand, as well as TNF-alpha and IL-1. None of these cell lines express CD3, but several express CD68 and CD71. In contrast, genomic investigations have shown the underlying existence of monoallelic and even biallelic gene rearrangements for TCR beta and IgJH. In view of these discrepancies between the genomic and phenotypic features of these cells, the histogenetic debate should remain open but must take into account these new chromosomal and molecular data.

Langerhans cell histiocytosis research. Past, present, and future

This article reviews the various investigative events that led to the endorsement of the term Langerhans cell histiocytosis for the various clinicopathologic conditions previously called Hand-Schüller-Christian disease, Abt-Letterer-Siwe disease, eosinophilic granuloma of bone, and histiocytosis X. The different denominations reflect the changing conceptual approaches to the so-called reticuloendothelial system and the successive acquisition of new ultrastructural and immunocytochemical data.

Contemporary classification of histiocytic disorders. The WHO Committee On Histiocytic/Reticulum Cell Proliferations. Reclassification Working Group of the Histiocyte Society

Pathologists and pediatric hematologist/ oncologists of the World Health Organization's Committee on Histiocytic/Reticulum Cell Proliferations and the Reclassification Working Group of the Histiocyte Society present a classification of the histiocytic disorders that primarily affect children. Nosology, based on the lineage of lesional cells and biological behavior, is related to the ontogeny of histiocytes (macrophages and dendritic cells of the immune system). Dendritic cell-related disorders of varied biological behavior are dominated by Langerhans cell histiocytosis, but separate secondary proliferations of dendritic cells must be differentiated. Juvenile xanthogranuloma represents a disorder of dermal dendrocytes, another dendritic cell of skin. The hemophagocytic syndromes are the most common of the macrophage-related disorders of varied biological behavior. Guidelines for distinguishing the exceedingly rare malignant diseases of histiocytes from large cell lymphomas through the use of a battery of special studies are provided.

Contemporary classification of histiocytic disorders. The WHO Committee On Histiocytic/Reticulum Cell Proliferations. Reclassification Working Group of the Histiocyte Society

Pathologists and pediatric hematologist/ oncologists of the World Health Organization's Committee on Histiocytic/Reticulum Cell Proliferations and the Reclassification Working Group of the Histiocyte Society present a classification of the histiocytic disorders that primarily affect children. Nosology, based on the lineage of lesional cells and biological behavior, is related to the ontogeny of histiocytes (macrophages and dendritic cells of the immune system). Dendritic cell-related disorders of varied biological behavior are dominated by Langerhans cell histiocytosis, but separate secondary proliferations of dendritic cells must be differentiated. Juvenile xanthogranuloma represents a disorder of dermal dendrocytes, another dendritic cell of skin. The hemophagocytic syndromes are the most common of the macrophage-related disorders of varied biological behavior. Guidelines for distinguishing the exceedingly rare malignant diseases of histiocytes from large cell lymphomas through the use of a battery of special studies are provided.

Regulation of TNF-alpha and IL-1 gene expression during TPA-induced differentiation of "Malignant histiocytosis" DEL cell line t(5;6) (q35:p21)

The production of TNF-alpha and IL-1 alpha and beta molecules has been shown to be associated with the proliferation and activation of cells of the monocyte/macrophage series, the intermediate steps in the synthesis of these molecules have been less investigated. Unstimulated and TPA stimulated DEL cells (a CD30-positive, t(5;6)(q35;p21) malignant histiocytosis cell line) were used to study the expression of TNF-alpha and IL-1 genes and to evaluate, by nuclear run-on assay and biological measurements, the control of their transcription and the level of protein production. To refine this analysis, the effects of cycloheximide and actinomycin D were also evaluated in this investigation. Following TPA stimulation, transcription of TNF-alpha (constitutively present) increased threefold as early as 30 mins and started decreasing by 24h. Cycloheximide superinduced the expression of TNF-alpha mRNA and, accordingly, the release of its protein. By contrast, transcription of IL-1 molecules appeared de novo and did not result in a biologically detectable protein. Measurements of RNA half line after actinomycin D indicated that TNF-a and IL-1 alpha mRNAs are not as stable as that of IL-1 beta. These results indicate that, despite their common synergistic activity, the transcriptional and post-transcriptional mechanisms regulating the synthesis of TNF-alpha and IL-1 alpha and IL-1 beta involve different pathways.

Malignant histiocytosis and large cell anaplastic (Ki-1) lymphoma in childhood: guidelines for differential diagnosis--report of the Histiocyte Society

A workshop of the Histiocyte Society was recently held, in order to discuss the problems and confusion of malignant histiocytosis (MH) and large cell anaplastic (Ki-1) lymphoma (LCAL). The aims of this workshop were to clarify the terminology for malignant histiocytic disorders and LCAL and to produce reliable criteria for diagnosis of both MH and LCAL. This article summarises the conclusions reached.

FLT4 receptor tyrosine kinase gene mapping to chromosome band 5q35 in relation to the t(2;5), t(5;6), and t(3;5) translocations

FLT4 is a recently cloned receptor tyrosine kinase cDNA, which is characterized by seven immunoglobulin-like loops in its extracellular domain. We have previously mapped the FLT4 gene to chromosome segment 5q33-qter using somatic cell hybrids. Here we have refined the localization to band 5q35 by fluorescence in situ hybridization and show that the gene is translocated to chromosomes 2 and 6 in the t(2;5)(p23;q35) and t(5;6)(q35;p21) translocations, respectively, of Ki-I-positive lymphomas, as well as to chromosome 3 in the t(3;5)(q25.1;q34) translocation, which is occasionally found in myelodysplastic syndromes and acute myeloid leukemia. No evidence was obtained for a rearrangement or deregulation of the translocated FLT4 gene. We further show that abundant FLT4 mRNA expression occurs only in erythroid and megakaryoblastoid cell lines among nine leukemia cell lines studied.

Modulation of c-myc, c-myb, c-fos, c-sis and c-fms proto-oncogene expression and of CSF-1 transcripts and protein by phorbol diester in human malignant histiocytosis DEL cell line with 5q 35 break point

Following exposure to phorbol ester (TPA), DEL cell line, a human malignant histiocytosis (MH) cell line, is able to differentiate along a macrophage phenotype and thus it provides a suitable model for analyzing the sequential and differential gene expression associated with monocyte/macrophage differentiation. C-myc, c-myb, c-fos, c-sis and c-fms expression were determined by Northern analysis at various times following TPA treatment. The results showed that TPA down-modulated the constitutive expression of c-myc, c-myb, and c-fms, mRNA to low but still detectable levels. Conversely, TPA-induced differentiation resulted in transient appearance of c-fos, whereas no change in the level of c-sis and actin transcripts were observed. Thus, the c-fms and c-sis genes appear to be regulated in a specific manner in this malignant histiocytosis derived cell line. Furthermore, these investigations demonstrated a constitutive CSF-1 gene expression which transiently increased at mRNA and also at protein level as evaluated by a murine bone marrow CFU bioassay. Through this drug-induced modulation, the DEL cell line offers an additional model for studying some of the subtle interrelations existing between a growth factor (CSF-1) and its receptor (c-fms) in the monocyte/macrophage system.

Thymic pathology in primary and secondary immunodeficiencies

For the sake of clarity and in agreement with the World Health Organization immunodeficiency classification, it is important to distinguish the congenital, inherited malformative lesions called generically 'thymic dysplasia' from the secondary, acquired changes, designated under the broad term of 'severe thymic atrophy'. Thymic dysplasia represents the archetype of thymic changes in cellular immunodeficiency, since there is no example of a thymic dysplasia associated with a normal T-cell function. Thymic dysplasia is observed in several inherited diseases, the most frequent of them being severe combined immunodeficiency. More than the depletion of lymphoid cells, the lack of differentiation of the thymic epithelium, responsible for the absence of Hassal's corpuscles, is the main and constant feature of this condition. Thymic dysplasia underscores the crucial role of the thymic epithelium in the normal differentiation of the T-cell population. Severe thymic atrophy is secondary to various causes, including prolonged protein malnutrition and immunosuppressive or cytotoxic drugs, graft versus host reaction and, chiefly today, chronic viral infection, especially with HIV-1. The morphological changes are similar and are characterized by a partial lymphoid depletion, involving mainly the CD1+ population, necrosis and calcification of epithelial cells, the frequent presence of plasma cells and, more significantly, fibrohyaline changes of the basement membrane of the vessels and thymic epithelium. The severity of the atrophic changes and the immunodeficiency-related manifestations depend on the duration of the aetiological factors and, more significantly, with their early occurrence, within the first months of life. The mechanisms underlying thymic atrophy are poorly understood. A primary impairment of lymphoid cells seems at present to be the most likely hypothesis.

Specific expression of the ras-related rab3A gene in human normal and malignant neuroendocrine cells

BACKGROUND

The authors originally demonstrated the tissue-specific expression of the rab3A gene in the mouse brain. In the current study, they analyze the activity of this gene in fresh human tumors associated with neuronal phenotype compared with normal and malignant cells from other origins.

METHODS

The authors studied the transcription levels of the rab3A gene by Northern blot in 81 fresh tumors.

RESULTS

A high rab3A gene expression was observed in tumor samples derived from the neural tube (i.e., neuroblastomas, ganglioneuroblastomas, and adult nervous system neoplasms). In addition, this tissue-specific expression extended to neuroendocrine tumors of the gut, small cell lung cancers, and pheochromocytomas.

CONCLUSIONS

These results suggest a specific restriction pattern to human cells derived from the neural tube and neural crests. The GTP/GDP-binding rab3A protein may be a useful differentiation marker of neuro-endocrine cells in the characterization of undifferentiated neoplasms.

Nucleolar organizer regions in congenital mesoblastic nephroma

A review of 78 renal tumors in patients under 6 months of age revealed 35 congenital mesoblastic nephromas (CMNs). Based on cellular criteria, 14 were classified as classical, 4 as partly cellular, and 17 as cellular CMN. The mean ages were 24, 11, and 70 days, respectively. There were 13 intrarenal tumors (stage I) but 9 classical, 3 partly cellular, and 5 cellular CMNs extended to the perirenal fat (stage II) and 5 cellular tumors ruptured (stage III). In order to assess cellular proliferative activity, silver staining of nucleolar organizer region (Ag-NOR) proteins was performed on 19 CMNs. The number of Ag-NOR dots per cell was significantly lower in classical and partly cellular CMN than in cellular CMN, whatever the stage (P < .01). Within the cellular CMNs, the mean number of Ag-NOR dots was statistically higher in the single case that recurred with fatal outcome (P < .02). Counting of Ag-NOR dots appears to be a reproducible method for evaluating the biologic potential of CMNs. The number of Ag-NOR dots, DNA content measurements, the histological subclassification, and the presence or absence of tumor at the surgical margins may be useful features in selecting those patients who will benefit from further treatment after nephrectomy.

Malignant histiocytosis in childhood: a distinctive CD30-positive clinicopathological entity associated with a chromosomal translocation involving 5q35

The clinicopathological data on 20 cases of malignant histiocytosis (MH) collected over a period of 30 years at the Hôpital des Enfants Malades (Paris) are reported. Childhood MH was characterized by disseminated, frequently tender lymphadenopathy (19/20), skin (8/20), bone (6/20), and soft tissue localizations (7/20). These features were usually accompanied by fever, deterioration of general condition, and hematological abnormalities including anemia, thrombocytopenia, and occasionally fibrinopenia. These manifestations were clinically suggestive of a diagnosis of a severe neoplastic blood disease, although this hypothesis was not entertained for a long time because of the initial absence of abnormal cells in the blood and bone marrow. MH was characterized by the proliferation of large "histiocyte-like," usually mononucleated cells. When suitable material was available, MH cells appeared to react positively with acid-phosphatase, alpha-naphthyl acetate esterase (ANAE), alpha-antichymotrypsin, and antibodies directed against EMA, HLA DR, CD25, CD30, CD68, and CD71. No B- and T-cell antigens (except for one case) have been detected. Due to the frequent abundance of accompanying granulocytes, lymphoid, and plasma cells, and the presence of areas of necrosis, an initial correct diagnosis of MH was often difficult to establish on skin (four cases), bone (two), and soft tissue (three) biopsies. In lymph nodes, the sinusoidal and perifollicular topography of cell proliferation represented a highly reliable morphological feature. A permanent cell line (DEL) was obtained from a pleural effusion showing a t(5;6)(q35;p21) translocation and a monoallelic immunoglobulin (IgjH) rearrangement and consistent levels of expression of c-fms, c-myc, c-myb, c-ki-ras and c-fgr. Since an identical 5q35 breakpoint has been reported in four other MH cell lines with a comparable phenotype and in several isolated published cases, this chromosomal abnormality provides a highly valuable argument for individualizing an authentic malignancy of the mononuclear phagocyte system (MPS) in childhood, among the rather heterogeneous group of the CD30+ anaplastic large cell lymphomas.

Human malignant histiocytosis CD30+ DEL cell line differentiates into macrophage-like cells when treated with a phorbol diester

The histiocytic or lymphoid origin of human malignant histiocytosis is currently a subject of debate. The aim of this study was to investigate the in vitro effects of 12-O-tetradecanoylphorbol-13-acetate used as a differentiation inducer on the CD30, t(5;6)(q35;p21) DEL cell line, taken to be a reliable representative of the human malignant histiocytosis cell line. Treatment of DEL cells with 33 nM 12-O-tetradecanoylphorbol-13-acetate for 6-24 h resulted in cell surface attachment (up to 80%), decrease in dividing ability, enhancement of nitro blue tetrazolium reducing capacity (from 8 to 42%), occurrence of a limited immunodependent phagocytosis, and transient increase in expression of tumor necrosis factor alpha gene and in production of tumor necrosis factor alpha protein, whereas tumor necrosis factor beta remained undetectable. From these data, we can conclude that the malignant histiocytosis DEL cell line is not of lymphoid origin but stems from a myelomonocyte lineage.

Lingual localization of an inclusion body fibromatosis (Reye's tumor)

This report illustrates a lingual localization of an inclusion body fibromatosis, the so-called Reye tumor or infantile digital fibromatosis (IDF). The light microscopic features were identical to those found in IDF, showing eosinophilic perinuclear inclusions located in spindle-shaped cells arranged in interlacing fascicles. The immunocytochemical and ultrastructural findings suggested a fibroblastic and/or myofibroblastic nature of the proliferative cells. However, the inclusions in our case were strongly stained with vimentin and their ultrastructural appearance was in keeping with intermediate filaments. These findings have never been described in other reports of fibromatosis. Whereas most reviews state that IDF occurs exclusively on the digits, this unique case describes its possible occurrence in the tongue.

[Gonadal dysgenesis and agenesis: anatomical expression]

The term of gonadal dysgenesis designates generically any anatomical alteration due to abnormal embryological development of a gonad. The spectrum of these gonadal abnormalities is large and includes the following entities: The gonadal agenesis is characterized by a rudimentary streak gonad. It is composed of a dense, hyalinized fibrous tissue in which the germ cells or the germ structures are entirely missing. Usually the gonadal dysgenesis is a bilateral and symmetrical lesion. The gonadal dysgenesis is characterized by the presence of residual germ structures (follicles or tubules). These structures can be more or less easily identified within a dense fibrous tissue. The gonadal dysgenesis alterations are often unilateral and always asymmetrical. Usually the ipsilateral gonad is a testis. The ovotestis is characterized by the coexistence within the same gonad of differentiated germ structures. Most commonly, the gonadal dysgenesis are associated with sexual chromosome abnormalities and an increased risk of neoplastic change (gonadoblastoma). This risk can reach 30% in the asymmetrical gonadal dysgenesis.

Chronic omphalitis in a 4-month-old girl

A case of chronic omphalitis present for birth in a 4-month-old girl is presented. The biopsy of the bud-like lesion failed to reveal a local malformation or remnants of umbilical cord but showed a common loose edematous tissue in which the inflammatory cells appeated remarkably scanty. The contrast existing between this poorly cellular local infiltrate and the high level of peripheral blood leucocytes (over 30,000/microliters) was in fact the most striking feature that allowed to evoke the diagnosis of Deficiency Leucocyte Adhesion molecules. Immunocytochemical investigations using anti CD11a, CD11b and CD18 monoclonal antibodies on fresh tissue or, better, peripheral leucocytes are necessary to confirm the diagnosis of this uncommon immunological autosomic recessive inherited disorder.

[Disseminated mucormycosis in pediatrics]

The case of a 14 month-old infant presenting with hereditary lymphohistiocytosis is reported. After several days of post-chemotherapy aplasia a peritoneal, cutaneous (blackish necrosis), then pleuropulmonary involvement occurred. Fiberendoscopy showed an esophageal necrosis responsible for a pleural fistula. The child died after a few weeks, despite antifungal treatment. Post mortem examination found disseminated abscesses related to mucormycosis. The 41 pediatric cases in the world-wide literature are recorded.

Genotype markers and proto-oncogene analysis in the CD30-positive "malignant histiocytosis" DEL cell line with t(5;6)(q35;p21)

The DEL cell line isolated from a patient who died of malignant histiocytosis exhibits a reciprocal chromosomal translocation t(5;6)(5q35;6p21). The cells were analyzed for Ig(Jh), TCR beta-gene rearrangements and proto-oncogene expression pattern, using a panel of molecularly cloned probes that included c-fms, c-myc, c-myb, c-pim, c-fos, N-myc, c-sis, c-fgr as well as the virally derived probes v-ki-ras and v-src. Consistent levels of expression of c-fms, c-myc, c-myb, c-ki-ras and c-fgr were identified in cells from several in vitro passages as well as from the heterotransplanted tumors in nude mice. Transcripts homologous to the c-fos, c-src and c-sis were not observed. Southern blot study of DNA showed that the banding pattern of the screened proto-oncogenes was not altered. Furthermore, Southern blot analysis demonstrated monoallelic immunoglobulin heavy chain (IgJh) rearrangement but a normal germ-line configuration of the kappa light chain and TCR beta-genes. These results appear to imply that a T- or B-cell origin can be eliminated and that several activated proto-oncogenes, usually expressed in immature MPS cells (c-fms) and myeloblastic cells (c-fgr), may be implicated in the proliferative activity of the DEL cell line, the stem of which may be a primitive, ancestral myelomonocytic cell.

[Primary interstitial pancreatitis or dyschylic pancreatitis in children. Apropos of 13 cases]

During a retrospective review of more than 1,000 pediatric pancreas specimens obtained by autopsy or biopsy, 13 cases of primitive interstitial pancreatitis (PIP) were identified. The morphologic diagnosis of PIP is based on the following histological features: presence of abundant, inspissated, PAS-negative intraductal secretions, overdistension and focal rupture of the intrapancreatic ducts, and presence of a focal, extensive inflammatory infiltrate. PIP should be distinguished from cystic fibrosis, necrotizing pancreatitis, and passive secondary interstitial infiltrates associated with extensive retroperitoneal cellulitis caused by septicemia or abdominal surgery. Clinical diagnosis is difficult and was not considered in the ten children under four years of age. In the three children over five, the presence of recurrent abdominal pain with mild ascitis and jaundice led to the correct diagnosis. Pathological findings suggest two possible pathophysiologic hypotheses: lesions may develop proximal to a mechanical malformative obstruction that is, however, only very rarely found, according to a more likely alternative, quantitative and qualitative modifications of pancreatic secretions may occur as a result of severe dehydration or use of drugs (corticosteroids, diuretics), justifying the term "dyschylic pancreatitis" coined by G. Seifert.

Cell differentiation in Wilms' tumor (nephroblastoma): an immunohistochemical study

Using an indirect immunoperoxidase technique, we tested frozen specimens from 12 Wilms' tumors with monoclonal antibodies (MoAbs) reacting against a large panel of molecules including laminin, fibronectin, cytokeratin, vimentin, villin, CD24, CALLA/CD10, CR1, CD26, class I and class II major histocompatibility complex (MHC) molecules, and endothelium factor VIII. These molecules were chosen because they are markers of specific segments of the mature kidney and because their loss or acquisition is indicative of different steps of human nephrogenesis. KI67 MoAb was used to evaluate the proliferating activity of the cells. The blastemal component (cell compact areas) of Wilms' tumors consisted of vimentin-positive cells with a fibronectin network. However, signs of epithelial maturation were present in compact areas where cytokeratin-positive cells producing laminin were observed. The cells exhibited a high degree of proliferating activity. The tubule formations consisted of cytokeratin-positive cells and had a defined laminin border. All the cells, whether in compact areas or in tubules, were strongly CD24-positive. Some tubular formations showed signs of proximal maturation with the presence of CALLA, CD26, and even villin. In four cases class I-MHC molecules were expressed by some tubular cells. Large cystic cavities present in five cases were edged by cytokeratin, CD24-positive cells, or by vimentin, CALLA, CR1-positive cells. Some glomeruloid bodies, present in two cases, were also composed of vimentin, CALLA, and CR1-positive cells which correspond to the mature podocyte phenotype. The interstitial tissue contained mainly laminin and fibronectin network with macrophages and few CD3 lymphocytes. The presence of large cells with muscular differentiation was noted; round vimentin and CD26-positive cells were also seen. The endothelial cells of the vessels exhibited vimentin, factor VIII, and class I and class II MHC molecules as do mature cells, but in some cases the endothelial cells lacked class II molecule expression and were CALLA-positive. These results which confirmed and extended those previously described show that cell differentiation in Wilms' tumor mimics that observed during metanephros development. Moreover, this study shows that tumoral cells in nephroblastoma share several antigens with cells from lymphoid lineage (CD24, CALLA, and CD26) as do developing and mature kidney cells. Such cell phenotype dissection provides a useful and reliable tool for testing the influence of various factors on the development of hetero-transplanted or cultured Wilms' tumors.

Different Epstein-Barr virus expression in lymphomas from immunocompromised and immunocompetent patients

Eighteen tissue samples from lymphoproliferative lesions and lymphomas in immunodeficiency states were investigated for their content of Epstein-Barr virus (EBV) genome by dot blotting and for the distribution of EBV in tissue sections by in situ hybridization. Fourteen lymphomas from AIDS patients and four children with disorders of the immune system were available. For control reasons, six cases of infectious mononucleosis (IM) and eight Burkitt's lymphomas (BL) from malaria-free regions of Africa were included in the study. Two different patterns of EBV distribution are described: 1) heterogeneous scattered EBV-positive cells, as originally seen in IM and therefore called the IM-type pattern, 2) and a BL-type pattern seen in endemic Burkitt's lymphoma with homogeneous EBV-positive cells all over the tumor. In lymphomas in patients with inborn immunodeficiencies, an IM-type pattern was found. In lymphomas from AIDS patients, the two different patterns were found. There were lymphomas with the IM-type pattern as well as some with the BL-type pattern. In some AIDS-associated lymphomas, both patterns occurred in one tumor. The findings suggest that it is not the disease process that is the distinguishing feature between the two patterns of EBV infection but rather the patient's underlying disease and the extent of this disease.

DEL cell line: a "malignant histiocytosis" CD30+ t(5;6)(q35;p21) cell line

A new cell line DEL, established in vitro, was isolated from a pleural effusion of a boy who died of malignant histiocytosis. Its principal characteristics are: strong positivity with monoclonal antibodies (MAbs) to CD25, CD30, CD45R, KiM7, EMA, HLA Cl I and II; constant presence of acid phosphatase, ANAE, alpha-anti-trypsin, alpha-anti-chymotrypsin and NBT reductase activity; rearrangement of the immunoglobulin heavy-chain gene (JH) and a germ-line configuration of the T-chain gene; and finally a translocation between chromosomes 5-6 with a breakpoint in 5q35. The DEL cell line is appropriate for studying the role of the 5q localized c-fms oncogene and of the genes of the mononuclear phagocyte growth factor (CSFI) and of their receptors in the dynamics and etiology of malignant hemopathies associated with a 5q35 breakpoint.

CD30-positive large cell lymphomas ('Ki-1 lymphoma') are associated with a chromosomal translocation involving 5q35

A chromosomal translocation involving a breakpoint on the long arm of chromosome 5 at position q35 has been reported previously in 17 cases of neoplasia. In 14 of these cases the translocation involves exchange of material between chromosome 2 p23 and chromosome 5. Most cases had been diagnosed histologically as malignant histiocytosis but it was suggested recently, following the study of three cases in one of the author's laboratories, that such tumours are in reality lymphoid tumours. In the present paper we report on 12 further neoplasms with a translocation involving the 5q35 breakpoint and show that all were large cell lymphomas expressing the CD30 (Ki-1) antigen, often classifiable histologically as 'Ki-1 lymphoma'. In five cases there was evidence, based on antigen expression and/or genotypic studies, that the neoplasm was of T lymphoid derivation. These findings provide further evidence that translocations involving 5q35 are associated not with histiocytic malignancy, but with large cell lymphoid neoplasms, including typical cases of 'Ki-1 lymphoma' or 'anaplastic large cell lymphoma'. Since cell lines have been established from five of these cases it may be possible in the future to clone the breakpoint on chromosome 5 and to investigate whether there is a gene in its vicinity with oncogenic potential.

[Sudden infant death syndrome]

Over the last 20 years, the sudden infant death syndrome has become the leading cause of death in infants aged one month to one year in developed countries. The SIDS Referral Centers set up in France have been assigned the task of performing thorough clinical, metabolic, infectious and histologic studies. This post-mortem evaluation, whose results are difficult to interpret, is undertaken in an attempt to discriminate between the multiple causes of conditions present at the time of death. This classification task will improve the definition of a number of risk factors. Among these factors, prematurity, perinatal distress requiring resuscitation, and an unfavorable sociocultural environment are often mentioned. Other factors, including intrauterine growth retardation, dysmorphic disorders, impaired regulation of ventilation, heart rhythm anomalies, and inherited defects in fatty acid metabolism are still under study since they are all infrequent. Various combinations of these factors may result in increased vulnerability to stress during the first months of life, the period when SIDS is most common. This ongoing research is indispensable for providing advice and support of the family and developing appropriate individual preventive measures for newborn SIDS siblings.

Congenital ciliary aplasia in two siblings. A primitive disregulation of ciliogenesis?

Congenital ciliary aplasia was demonstrated in two siblings with clinical history of primary ciliary dyskinesia. Ultrastructural histochemistry of successive bronchial biopsies revealed the predominance of immature mucous cells and the total absence of ciliated or preciliated cells in the respiratory epithelium. This original disorder may represent a unique variant of primary ciliary dyskinesia with primitive disregulation of ciliogenesis.

[T lymphoma of the nasopharynx, a rare entity. Apropos of a case]

We report one case of nasal T-cell lymphoma (NTL) that we studied histologically and with a panel of monoclonal antibodies. It is a rare etiology of the so-called lethal midline granuloma. The diagnosis of NTL if often difficult because of spreading necrosis, cellular polymorphism and necessity of getting frozen snap sections for immunohistochemical techniques. We describe histological, immunohistochemical features of NTL and its usual follow up. Then we compare them with those of malignant lymphomas of the Waldeyer's ring which are very different although they are located very near to NTL. These differences raise the hypothesis of a possible role of the local environment.

Lymphadenopathy in renal transplant patients treated with immunosuppressive antibodies (OKT3 and anti-thymocyte globulin). A report of nine cases

A clinicopathological study of nine patients who developed systemic lymphadenopathy following renal transplantation and immunosuppressive therapy (OKT3 and anti-thymocyte globulin) showed a rapidity of onset and disappearance of lymphadenopathy (nine of nine cases), a frequent association of systemic signs (nine of nine cases), and a heterogeneity of histological patterns ranging from diffuse lymphoid hyperplasia to one incorrectly considered to be immunoblastic lymphoma. The coexpression of both light chains was useful in the exclusion of the diagnosis of B lymphoma. These posttransplant lymphoproliferative syndromes seem to represent an allergic reaction to the introduction of foreign protein resembling serum sickness rather than a viral infection favored by immunosuppression, although in one case (with pseudolymphomatous features) a virus was the likely mechanism.

Primary intestinal myopathy, a cause of chronic idiopathic intestinal pseudoobstruction syndrome (CIPS): clinicopathological studies of seven cases in children

Clinicopathological data on seven instances of primary intestinal myopathy in children are reported. The ages of the patients ranged from eleven months to thirteen years. A persistent intestinal obstruction was the main and constant clinical feature. An ineffective intestinal propulsion was documented on manometric studies. Various urological abnormalities were present in three cases. One patient died and six survive but are dependent on enteral and parenteral nutrition. The morphological findings consisted of degenerative changes involving the muscular layers of the intestinal wall. These changes varied from cytoplasmic vacuolation to definite atrophy and disappearance of the muscular fibers. An extensive interstitial fibrosis underlined these atrophic changes in the late stages of the disease. A familial history was identified in three cases, one consistent with an autosomal dominant transmission.

The disappearance of germinal centers in chronic lymphadeno-hepato-splenomegaly syndrome in childhood: report of three cases

Three cases of a syndrome featuring massive splenomegaly, gross generalized lymphadenopathy, and moderate hepatomegaly are reported. Spleen weights ranged from 800 to 2400 g. Gradual depletion of lymphoid germinal centers, and prominent infiltration of the splenic and lymph node cords with plasma cells, immunoblasts and actively dividing B cells were the most distinctive histological features. The liver in two cases showed portal infiltrates. A marked hypergammaglobulinemia, a decrease in blood cholesterol level and hematological abnormalities related to hypersplenism were observed. The condition begins early in life and runs a chronic course, of up to 25 years. There was a family history in only one instance. Since there was no generalized immunodeficiency nor local depletion of T cells or dendritic reticulum cells, a failure in the local regulation of the immune response and possible cytokine production is postulated. This condition underlines the pivotal role of the local organization of the germinal centers in cellular cooperation and in the carrying out and regulation of the immune response.

Solitary intestinal fibromatosis: a rare cause of neonatal obstruction

Solitary intestinal fibromatosis (SIF) is an unusual cause of neonatal intestinal obstruction. A fibromatosis located in the first part of the duodenum, close to the pylorus, was associated with a focus of heterotopic pancreas and mimicked congenital pyloric stenosis. It illustrates the difficulties encountered in the diagnosis and surgical management of this condition.