SEARCH · PubMed Health

Results for “HISTIOCYTES”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources

PubMed1984

Characterization of immature sinus histiocytes (monocytoid cells) in reactive lymph nodes by use of monoclonal antibodies.

The distinctive mononuclear cells that appear in the cortical sinuses of lymph nodes in toxoplasma lymphadenitis and other conditions have been termed "immature sinus histiocytes," although these cells have neither enzyme histochemical nor ultrastructural features of histiocytes. The authors stained these cells in frozen sections of six reactive lymph nodes, using the immunoperoxidase technique, with monoclonal antibodies to T cell, B cell, and monocyte antigens and with heteroantisera to immunoglobulin and lysozyme. The immature sinus histiocytes stained with a monoclonal antibody to B cells (anti-B1) and had immunoglobulin of the IgG class. They did not react with monoclonal antibodies to T cells or monocytes or with antilysozyme. In contrast, medullary sinus histiocytes in three additional lymph nodes were B1-negative and reacted with anti-T4, anti-M1, and anti-lysozyme. These results indicate that immature sinus histiocytes are IgG-bearing B lymphocytes rather than histiocytes. Their role in the immune response remains enigmatic.

Antibodies, Monoclonal↗

PubMed1986

Familial erythrophagocytic lymphohistiocytosis: immunophenotypic, immunohistochemical, and ultrastructural demonstration of the relation to sinus histiocytes.

Familial erythrophagocytic lymphohistiocytosis (FEL), a rare, rapidly fatal childhood disease, is characterized by fever, hepatosplenomegaly, pancytopenia, and widely disseminated lymphohistiocytic infiltrates with prominent erythrophagocytosis. Immunophenotypic, immunohistochemical, and ultrastructural studies of two siblings with FEL were performed in an effort to determine the nature of the proliferating histiocyte of FEL. These studies demonstrated that the FEL histiocytes lack S-100 protein, T6, and Birbeck granules, which are found in Langerhans and interdigitating dendritic cells. The FEL histiocytes express alpha 1-antichymotrypsin, Leu-M3, HLA-DR, and, variably, lysozyme and Leu-M1. Thus, the proliferating histiocyte of FEL is a member of the mononuclear phagocytic system and has a phenotype similar to that of the histiocytes that normally populate the sinuses of benign and reactive lymph nodes. These studies suggest that FEL may represent uncontrolled proliferation of sinusoidal histiocytes.

Antigens, Differentiation, T-Lymphocyte↗

PubMed1987

Sinus histiocytosis with massive lymphadenopathy. A nodal and extranodal proliferation of S-100 protein positive histiocytes?

Four cases of sinus histiocytosis with massive lymphadenopathy (SHML) from Finland were studied clinically and immunohistologically. Three patients had histologically verified extranodal manifestations that often caused the most prominent clinical symptoms. Upper respiratory tract obstruction resulting from SHML lesions was present in two cases, multiple bone lesions in one case, and skin lesions in one case. Clinical remission was observed in all cases, but the course was often protracted. Immunohistochemical studies revealed S-100 protein and alpha-1-antichymotrypsin (ACT) positivity in most large pale cytoplasmic histiocyte-like cells in all cases, whereas lysozyme was not present in these cells. Sinus cells in ordinary sinus histiocytosis were constantly positive for ACT and variably positive for lysozyme and were generally negative for S-100 protein. The large histiocyte-like cells in SHML resemble interdigitating reticulum cells and Langerhans' cells in their S-100 protein positivity but differ from these cells by morphologic characteristics and the presence of alpha-1-antichymotrypsin, a marker constantly seen in ordinary histiocytes. These results suggest that SHML is a proliferative condition of histiocyte-related cells, which share some properties of histiocytes and some of interdigitating reticulum cells. Further studies are necessary to clarify the nature of the peculiar histiocyte-like cells in SHML.

Adolescent↗

PubMed1980

Primary histiocytic lymphoma of bone: a light and ultrastructural study of four cases.

The light and ultrastructural features of primary histiocytic lymphoma of bone are indistinguishable from similar studies of respective cell types of nodular and diffuse large cell nodular and extranodal lymphomas. These ultrastructural features add further support to their lymphocytic histogenesis. There was no relationship between increasing nuclear clefts and convolutions in individual cases and the ultrastructural presence of increasing "histiocytic" features. Primary histiocytic lymphoma of bone is not a completely uniform monomorphic tumor cell population, but may vary in percentage of large noncleaved, large cleaved, large convoluted lymphocytic, histiocytic, and small atypical lymohocytic cells. Detailed study of four cases enabled division into two primary subgroups: Type I, consisting of a predominance of large noncleaved cells; and Type II, consisting of a mixture of cleaved, noncleaved, and convoluted cells. Further cases are being studied to determine whether these two groups are distinct or merely represent part of a continuous spectrum of cellular pleomorphism. In contrast to nodal lymphomas, there is no evidence at this time that proportional variations in the tumor cell population bear any relationship to biologic behavior or survival. Glycogen may be present in histiocytic lymphomas but was very rare (less than 1% total cells). Therefore, this feature as an isolated observation will not differentiate histiocytic lymphoma from Ewing's sarcoma.

Adult↗

PubMed1991

Immunophenotypic analysis of histiocytes involved in AIDS-associated Mycobacterium scrofulaceum infection: similarities with lepromatous lepra.

The present study reports a rare case of systemic M. scrofulaceum infection in an AIDS patient and analyses the inflammatory infiltrate in a lymph node by immunohistochemistry. Special emphasis is put on the histiocytes. The diffuse infiltrate consists mainly of large histiocytes that contain numerous bacilli. These cells display the phenotype of mature histiocytes and in addition coexpress the antigens recognized by RFD7 and RFD9, both markers of different subsets of histiocytes which have been reported to be co-expressed by the infected histiocytes in the infiltrate of lepromatous lepra. Interdigitating reticulum cells are rare as well as T cells which are mainly of the suppressor/cytotoxic type. These findings are similar to those reported for lepromatous lepra and might indicate common deficiencies in T cell-macrophage interactions in both conditions. Superimposed on the diffuse infiltrate of large histiocytes we observed 'monocytic granulomas', the presence of which might be related to a reactional state comparable to erythema nodosum leprosum, a reactional state of lepromatous lepra.

Acquired Immunodeficiency Syndrome↗

PubMed1987

Identification of tissue histiocytes on paraffin sections by a new monoclonal antibody.

A mouse monoclonal antibody (MAC 387) with specificity for monocytes and tissue histiocytes was produced by immunization of a BALB/c mouse with peripheral blood monocyte components derived by affinity chromatography of detergent-solubilized monocyte material on Sepharose 4B coupled to rabbit anti-monocyte antibodies. MAC 387 strongly stained the cytoplasm of cells of the monocyte/macrophage series on paraffin sections after controlled trypsinization of sections. The antibody showed broad reactivity for a variety of tissue histiocytes, including infiltrating and reactive histiocytes, alveolar macrophages, Kupffer cells, follicle-center macrophages, splenic red pulp macrophages, tumor-infiltrating macrophages, sinus histiocytes, epithelioid giant cells (variably), and cases of histiocytosis X and dermatopathic lymphadenopathy. Molecular weight data obtained by Western blotting, immunoprecipitation, and immunoaffinity-purification revealed that the antigen was present in different forms in the monocyte and granulocyte. In the granulocyte, free alpha (Mr 12 KD) and beta (Mr 14 KD) chains expressing the MAC 387 epitope were found together with associations of one alpha and one beta chain linked by disulfide bonds to yield a heterodimer of Mr 26 KD. In the monocyte, free alpha and beta chains are not found, but instead the heterodimer and associations of two (Mr 56 KD) and four (Mr 112 KD) heterodimers are disulfide-linked together. This new monoclonal reagent should have particular value for identification of tissue histiocytes in routine paraffin sections and particularly for demonstration of histiocytes in malignant lymphomas.

Animals↗

PubMed2006

Canine hemophagocytic histiocytic sarcoma: a proliferative disorder of CD11d+ macrophages.

Histiocytic disorders of dogs include histiocytoma, localized histiocytic sarcoma (HS), disseminated HS (malignant histocytosis), and the reactive histiocytoses: cutaneous and systemic. A common element to these diseases is proliferation of dendritic cells (DC) of either Langerhans cell (epithelial DC) or interstitial DC lineage. In this report, 17 dogs with hemophagocytic HS are described. Breeds affected included Bernese Mountain Dog (6), Golden Retriever (4), Rottweiler (3), Labrador Retriever (2), a mixed-breed dog, and a Schnauzer, which were from 2.5 to 13 years old. The dogs presented with Coombs negative responsive anemia in 16/17 dogs (94%), thrombocytopenia in 15/17 dogs (88%), hypoalbuminemia in 16/17 dogs (94%), and hypocholesterolemia in 11/16 dogs (69%). All dogs died or were euthanized. The clinical course ranged from 2 to 32 weeks (mean 7.1 weeks). Diffuse splenomegaly with ill-defined masses was consistently present. Microscopic lesions were prevalent in spleen, liver, lung, and bone marrow. Metastasis occurred by insidious intravascular invasion with minimal mass formation. Histiocytes were markedly erythrophagocytic and accompanied by foci of extramedullary hemopoiesis. Cytologically, the histiocytes varied from well differentiated to atypical, with atypia more prevalent in spleen than bone marrow. These tumors arose from splenic red pulp and bone marrow macrophages, which expressed major histocompatibility complex class II and the beta2 integrin, CD11d. They had low and/or inconsistent expression of CD1 and CD11c, which are dominantly expressed by canine nonhemophagocytic HS of DC origin. Canine histiocytic proliferative diseases now encompass proliferation of all members of the myeloid histiocytic lineage: Langerhans cells, interstitial DC, and macrophages.

Animals↗

PubMed1985

Primary histiocytic dermatoses.

The physiology of the histiocyte (macrophage) in health and disease is reviewed briefly. An overview of the so-called primary malignant, pseudomalignant, and benign histiocytic disorders, excluding histiocytosis X, is presented. The malignant histiocytosis with erythrophagocytosis, the pseudomalignant histiocytic diseases (such as sinus histiocytosis with massive lymphadenopathy and regressing atypical histiocytosis), and the solitary lesions with histologic malignant and atypical storiform histiocytosis are described. Two groups of adult histiocytic diseases are reviewed; one is characterized by nonfamilial and familial histiocytic dermatoarthritis and the other by multiple widespread benign lesions, such as xanthoma disseminatum, generalized eruptive histiocytoma, nodular non-X histiocytosis, and various xanthomatous eruptions associated with paraproteinemia. Finally, multiple benign cutaneous histiocytic lesions of childhood, such as juvenile xanthogranuloma and congenital self-healing histiocytosis, are included.

Adult↗

PubMed1985

[Histiocytic proliferative diseases].

Proliferation of the mononuclear phagocyte system cells is the basis for histiocytic proliferative conditions (malignant histiocytosis, histiocytic "reticulosarcoma" histiocytosis X). Cells of the phagocytosing histiocyte type proliferate in malignant histiocytosis and histiocytic "reticulosarcoma), cells of the Langerhans type proliferate in histiocytosis X. According to Rappaport's classification of 1966, histiocytic "reticulosarcoma" is separated from the heterogeneous group of diffuse histiocytic lymphomas. Its morphological picture is non-distinguishable from that of malignant histiocytosis, particularly at the stage of generalization. The Letterer-Siwe disease due to its course, prognosis and special therapeutical approach should be separated from the group of conditions combined under the term "histiocytosis".

Diagnosis, Differential↗

PubMed1982

The isolated finding of histiocytes in Papanicolaou smears from postmenopausal women.

The effectiveness of uncovering uterine disease by drawing special attention to increased histiocytes on Papanicolaou smears from postmenopausal patients was evaluated during a 22-month period. Of the 95,593 screened, 478 had increased histiocytes. Half the patients did not have specific follow-up during the study period. One-third had repeated Papanicolaou smears, which were usually unremarkable and free of increased histiocytes. Seventy-eight patients had subsequent endometrial sampling, hysterectomy or both; 41 of these samples failed to disclose pathology. Thirty-seven cases did yield abnormal tissue. However, when the clinical records of those patients were analyzed, it appeared that most had postmenopausal bleeding or an abnormal physical finding. Of five cases in which the finding of increased histiocytes apparently led to uncovering significant uterine disease, two had endometrial cells reported on the Papanicolaou smear in question. There remained only three cases in which the isolated presence of increased histiocytes led to the discovery of disease; they included one instance of adenomatous endometrial hyperplasia and two of endometrial polyp. We conclude that the isolated finding of increased histiocytes in the absence of postmenopausal bleeding or endometrial cells in a postmenopausal patient is a poor indicator of uterine disease. Such a finding, on its own, is insufficient justification for recommending a diagnostic tissue biopsy.

Adenocarcinoma↗

PubMed1983

T-zone histiocytes with S100 protein. Development and distribution in human fetuses.

Histiocytic cells with S100 protein compose a cell lineage independent of the monocyte-macrophage system. Langerhans cells and indeterminate cells in the skin and oral mucosa, interdigitating cells in the T-zone of the lymph node, and other lymphoid tissues belong to this cell lineage. In addition to these cells, small S100+ cells showed morphological transition to large histiocytes. In human fetuses, a large number of S100+ lysozyme- NCA- cells first appeared in the thymic medulla by the end of the third month of gestation, and rapidly disseminated to the various lymphoid organs in accordance with the spread of T-lymphocytes during the fourth month of gestation. S100+ small cells were more frequent than large cells and showed more rapid dissemination in the early stage. S100- lysozyme+ NCA+ immature macrophages appeared in the liver, spleen, lymph node anlage, and other tissues at the second month of gestation, and their distribution was completely different from S100+ histiocytes. Fetal development of T-zone histiocytes with S100 protein supported the hypothesis that there are two histiocytic cell lines; one is the monocyte-macrophage system, another is the S100+ T-zone histiocyte system.

Carcinoembryonic Antigen↗

PubMed1994

Histiocytes and histiocytosis.

The term histiocyte refers to cells of either the macrophage or Langerhans cell lineages. The histiocytic disorders are characterized by the proliferation of cells of these lineages. With recent advances in knowledge of the developmental biology of histiocytic cells, it is now possible to formulate a reasonable catalogue of histiocytic diseases based on ultra-structural and phenotypic markers of cellular origins and molecular or chromosomal markers of malignancy. The catalogue includes the following groups of diseases. Nonmalignant reactive macrophage disorders include (1) macrophage storage diseases, (2) several benign proliferative macrophage disorders that predominantly involve skin and bone, and (3) several hemophagocytic syndromes that vary from indolent and benign to fulminant and fatal. In some of the latter disorders, viruses have been identified as the inciting stimulus. The malignant macrophage disorders include (1) acute monocytic leukemia and (2) chronic myelomonocytic leukemia. A rare disorder that gave rise to a permanent cell line with an anomaly of chromosomal segment 5q35 may also be an example of a histiocytic malignancy. The existence of a separate category of true histiocytic lymphoma of macrophage type is uncertain. Reactive Langerhans cell disorders include (1) congenital self-healing histiocytosis, (2) the many variants of eosinophilic granuloma, and (3) a related disorder designated as relapsing Langerhans cell histiocytosis that is characterized by a relapsing course and infiltration of bone and soft tissues by Langerhans cells. Presumptively neoplastic diseases of Langerhans and dendritic cells include (1) progressive Langerhans cell histiocytosis, a disease with prominent involvement of blood and BM as well as skin and viscera; (2) Langerhans cell lymphoma, and (3) dendritic cell lymphoma. However, clonality as a marker of malignancy has not been proven in these disorders.

Antigens, CD↗

PubMed1990

Phenotypic and genotypic analysis of large-cell lymphomas, formerly classified as true histiocytic lymphoma: identification of an unusual group of tumors.

A group of 12 large-cell lymphomas, seen in the period January 1983 to January 1985 and then tentatively classified as histiocytic sarcomas/true histiocytic lymphomas (i.e. non B-, non T-cell lymphomas, with expression of some histiocytic markers) were restudied phenotypically with a much more extensive range of monoclonal and polyclonal antibodies. They were also genotypically analyzed with respect to rearrangements of genes coding for the immunoglobulin (Ig) heavy and light chains and the gamma and beta chains of the T-cell receptor (TCR). The combined results suggest that these "histiocytic sarcomas" represent a heterogeneous group of large cell lymphomas often with unexpected rearrangements (or lack of rearrangements) of either Ig and TCR genes and phenotypically with coexpression of "histiocytic" and B- or T-cell markers. Such coexpression may be regarded as a warning signal to expect unusual genotype. True histiocytic tumours apparently do exist, but are rare (one case in this study), and their diagnosis is very difficult.

Antigens, Differentiation↗

PubMed1993

True histiocytic lymphoma of small intestine. Analysis of two S-100 protein-positive cases with features of interdigitating reticulum cell sarcoma.

Two cases of true histiocytic lymphoma of the small intestine occurred in middle-aged patients, manifesting as tumors causing intestinal obstruction. One of the patients died of uncontrollable local and metastatic disease, 16 months after surgery and polychemotherapy, and the other patient is alive 12 months after surgery and chemotherapy. The histologic characteristics of the tumor cells, namely complex nuclear outlines and abundant variably eosinophilic cytoplasm, suggested histiocytic differentiation. Both cases had negative results for B-cell and T-cell markers but stained for the histiocytic markers lysozyme, CD68, and HLA-DR and had positive results for S-100 protein and vimentin. Acetone-fixed frozen sections of one case showed positive results for several histiocytic markers, including CD11c, CD14, CD33, CD68, and BerMac3 (unclustered monoclonal antibody). CD4, a T-cell antigen present in a subset of histiomonocytic cells, had positive results in the cytoplasm. The tumor cells had negative results for CD1a, CD15, and CD30. Immunoglobulin and T-cell receptor gene probes showed germline configuration in one case studied. These results indicate the tumors are true histiocytic lymphomas, which have immunophenotypic features of both ordinary histiocytes and interdigitating reticulum cells.

Antigens, CD↗

PubMed1996

Histiocytic sarcoma that mimics benign histiocytosis.

A 28-year-old man presented with a histiocytic sarcoma of a very uncommon origin, as it had developed for several years like a benign cutaneous histiocytosis resembling generalized eruptive histiocytoma before becoming acute, with nodal and massive pulmonary involvement. Despite various chemotherapies, the patient died within 8 months. Skin biopsies showed histiocytic proliferation in the dermis and node biopsies showed histiocytic proliferation with a sinusoidal pattern. Immunohistochemical analysis, performed on paraffin-embedded sections, demonstrated strong labeling of tumoral cells for CD68 and moderate labeling for CD3 and CD4. CD30 labeling was negative. S-100 protein was positive on a Langerhans' cell reactive subpopulation. Electron microscopy confirmed the histiocytic nature of malignant cells and showed cytoplasmic inclusions such as regularly laminated bodies, dense bodies and pleomorphic inclusions. No Birbeck granules were seen. A gene rearrangement study of T-cell receptor gamma and immunoglobulin heavy chain genes showed a germline configuration. Histiocytic sarcoma is an extremely rare true histiocytic malignancy, the existence of which has been recently debated since it has often been mistaken in the past for large cell lymphomas. Such a deceptive onset as benign cutaneous histiocytosis has not been described in the literature to our knowledge.

Adult↗

PubMed1993

Expression of mononuclear phagocyte antigens in histiocytic sarcoma of mice.

Twenty cases of histiocytic sarcoma in 15 female and five male (384 to 722 days of age) hybrid F1 (C57BL/6 x BALB/c) or F2 (F1 x F1) mice were studied for expression of mononuclear phagocyte and other antigens. Histiocytic sarcomas were found most often in liver, uterus, spleen, and lung. Tissues fixed in Bouin's fluid provided preservation of antigen immunoreactivity, using avidin biotin peroxidase complex immunohistochemistry, with monoclonal and polyclonal antibodies. The mononuclear phagocyte antigens, lysozyme and Mac-2 (a galactose-specific lectin that binds IgE), were found in 60-70% of the cases. The receptor for the macrophage colony-stimulating factor (CSF-1), c-fms, was expressed in 2/20 (10%) of the cases. Mouse immunoglobulins were not found in histiocytic sarcoma cells. In uterine histiocytic sarcomas, previously reported as Schwannomas because of their histologic appearance, S-100 protein was not expressed by tumor cells, although they usually expressed Mac-2 and lysozyme. Hyaline droplets were found in the renal tubules of only 2/19 cases. Our studies provide evidence that murine histiocytic sarcoma expresses antigens (Mac-2, lysozyme, c-fms) found in cells of the mononuclear phagocyte series, in contrast to the B-cell origin of many human histiocytic tumors.

Animals↗

PubMed1992

Histiocyte-rich B-cell lymphoma. A distinct clinicopathologic entity possibly related to lymphocyte predominant Hodgkin's disease, paragranuloma subtype.

This study reports six non-Hodgkin's lymphoma cases that we called histiocyte-rich B-cell lymphoma (BCL) because of the prominent reactive histiocytic infiltrate obscuring the malignant B-cell population. The involved lymph nodes are characterized by a mixed nodular and diffuse infiltrate and occasionally feature prominent sinuses. The infiltrate is composed of reactive lymphocytes and numerous histiocytes obscuring a tumor population composed of variably sized scattered cells with irregular or multilobar vesicular nuclei. Immunostaining of paraffin sections for the B-cell marker recognized by L26 helps in the identification of these neoplastic cells. The clonal nature and further evidence of the B-cell lineage of this condition is shown by immunoglobulin gene rearrangements detected in three cases. The six cases of histiocyte-rich BCL are remarkably similar clinically: all presented with stage IVB disease with splenomegaly and follow an aggressive clinical course. Except for these features, our series show striking similarities to paragranuloma lymphocyte-predominant Hodgkin's disease, including male preponderance (all patients are male), age distribution (mean age, 41 years), propensity to progress to a diffuse, large B-cell lymphoma (two cases), as well as morphology of the neoplastic B-cell population and expression of Hodgkin's cell markers (Leu-M1 positivity after neuraminidase digestion in three cases, Leu-M1 positivity without neuraminidase digestion in one case, and additional epithelial membrane antigen [EMA] positivity in two cases). Both morphologically and clinically, the present series can be differentiated from other types of infiltrate-rich BCL, such as T-cell-rich BCL. Although additional cases will have to be recognized, histiocyte-rich B-cell lymphoma most likely represents a distinct clinicopathological entity. We speculate that it develops from a subset of B cells that also gives rise to the lymphocytic-histiocytic (L/H) cell, the Hodgkin's cell variant of lymphocyte-predominant Hodgkin's disease, paragranuloma subtype.

Adult↗

PubMed2002

Tumours of histiocytes and accessory dendritic cells: an immunohistochemical approach to classification from the International Lymphoma Study Group based on 61 cases.

Neoplasms of histiocytes and dendritic cells are rare, and their phenotypic and biological definition is incomplete. Seeking to identify antigens detectable in paraffin-embedded sections that might allow a more complete, rational immunophenotypic classification of histiocytic/dendritic cell neoplasms, the International Lymphoma Study Group (ILSG) stained 61 tumours of suspected histiocytic/dendritic cell type with a panel of 15 antibodies including those reactive with histiocytes (CD68, lysozyme (LYS)), Langerhans cells (CD1a), follicular dendritic cells (FDC: CD21, CD35) and S100 protein. This analysis revealed that 57 cases (93%) fit into four major immunophenotypic groups (one histiocytic and three dendritic cell types) utilizing six markers: CD68, LYS, CD1a, S100, CD21, and CD35. The four (7%) unclassified cases were further classifiable into the above four groups using additional morphological and ultrastructural features. The four groups then included: (i) histiocytic sarcoma (n=18) with the following phenotype: CD68 (100%), LYS (94%), CD1a (0%), S100 (33%), CD21/35 (0%). The median age was 46 years. Presentation was predominantly extranodal (72%) with high mortality (58% dead of disease (DOD)). Three had systemic involvement consistent with 'malignant histiocytosis'; (ii) Langerhans cell tumour (LCT) (n=26) which expressed: CD68 (96%), LYS (42%), CD1a (100%), S100 (100%), CD21/35 (0%). There were two morphological variants: cytologically typical (n=17) designated LCT; and cytologically malignant (n=9) designated Langerhans cell sarcoma (LCS). The LCS were often not easily recognized morphologically as LC-derived, but were diagnosed based on CD1a staining. LCT and LCS differed in median age (33 versus 41 years), male:female ratio (3.7:1 versus 1:2), and death rate (31% versus 50% DOD). Four LCT patients had systemic involvement typical of Letterer-Siwe disease; (iii) follicular dendritic cell tumour/sarcoma (FDCT) (n=13) which expressed: CD68 (54%), LYS (8%), CD1a (0%), S100 (16%), FDC markers CD21/35 (100%), EMA (40%). These patients were adults (median age 65 years) with predominantly localized nodal disease (75%) and low mortality (9% DOD); (iv) interdigitating dendritic cell tumour/sarcoma (IDCT) (n=4) which expressed: CD68 (50%), LYS (25%), CD1a (0%), S100 (100%), CD21/35 (0%). The patients were adults (median 71 years) with localized nodal disease (75%) without mortality (0% DOD). In conclusion, definitive immunophenotypic classification of histiocytic and accessory cell neoplasms into four categories was possible in 93% of the cases using six antigens detected in paraffin-embedded sections. Exceptional cases (7%) were resolvable when added morphological and ultrastructural features were considered. We propose a classification combining immunophenotype and morphology with five categories, including Langerhans cell sarcoma. This simplified scheme is practical for everyday diagnostic use and should provide a framework for additional investigation of these unusual neoplasms.

Adult↗