Hepatosinusoidal leukaemia/lymphoma consisting of epstein-barr virus-containing natural killer cell leukaemia/lymphoma and T-cell lymphoma; mimicking malignant histiocytosis

Previously diagnosed cases of hepatosinusoidal T-cell lymphoma and malignant histiocytosis (MH) may include lymphoid neoplasms of natural killer (NK) cell lineage associated with Epstein-Barr virus (EBV). Such hepatosinusoidal neoplasms were found to demonstrate hepatomegaly but not lymphadenopathy, and all were diagnosed by a liver biopsy. Sixteen adult patients diagnosed with hepatosinusoidal leukaemia/lymphoma (six NK-cell leukaemia/lymphomas [NKLLs], five instances of MH, three T-cell malignant lymphomas [T-MLs], and two adult T-cell leukaemia/lymphomas [ATLLs] were examined for EBV by in situ hybridization, then were studied immunohistochemically and subjected to a DNA analysis. Among our five patients with MH, neoplastic cells showed T-cells, but no histiocytic markers, and they were considered to have either a T-cell or NK-cell lineage. All NKLLs, MHs and T-MLs, except for ATLLs accompanied by reactive hemophagocytic histiocytes, varied in number in each case. In situ hybridization revealed the presence of EBV in the nuclei of atypical cells in all of the six lymphoid neoplasms of NK-cell lineage. Each case of MH and each T-ML which represented EBV demonstrated no definite T-cell or histiocytic markers. Patients with ATLL did not reveal EBV. In all patients with hemophagocytosis, EBV was present in the nuclei of the neoplastic lymphocytes, but not in the hemophagocytic cells. Finally, the 16 cases were reclassified into eight cases with EBV -containing NKLLs, six T-MLs, and two ATLLs. In addition, no true histiocytic neoplasms were observed. The mechanism of hemophagocytosis may be therefore the production of lymphokines (macrophage-activating factors) by neoplastic lymphocytes. EBV-associated hepatosinusoidal leukaemia/lymphoma may thus contain a lymphoid neoplasm of NK-cell lineage, which made it difficult to be distinguished from the previously designated malignant histiocytosis.     

An investigation of Ki-1 positive large cell lymphoma with antibodies reactive with tissue macrophages

The diagnosis of true histiocytic lymphoma (THL) represents one of the most difficult and controversial areas of lymph node pathology. Recently, Stein et al. (1985) have demonstrated that a series of tumours presenting with morphological and immunocytochemical features, previously considered as being indicative of THL, share antigenic markers with Reed-Sternberg and mononuclear Hodgkin's cells and, therefore, may be derived from lymphocytes, rather than histiocytes. In this study we have re-investigated some of these cases with a panel of monoclonal antibodies variously reactive with macrophages. Although all cases contain a heavy infiltrate of reactive histiocytes the tumour populations are negative for histiocyte antigens.     

Malignant histiocytosis and Letterer-Siwe disease. Neoplasms of T-zone histiocyte with S100 protein

Eight cases with malignant histiocytosis (MH), two cases with systemic Letterer-Siwe disease, and one case with sarcomatous variant of MH were studied clinicopathologically. Characterization of neoplastic histiocytes was performed by immunohistochemical staining for S100 protein, lysozyme, and nonspecific cross reacting antigen with carcinoembryonic antigen (NCA). The immunohistochemical characteristics of histiocytes were S100+lys-NCA- in eight MH and two Letterer-Siwe disease cases and S100-lys+NCA+ in the sarcomatous variant of MH. MH and Letterer-Siwe disease were considered to have derived from a specific S100+ histiocytic cell lineage (T-zone histiocyte with S100 protein) independent of the monocyte--macrophage system, from which a sarcomatous variant was derived. Leukemic change of MH was discussed with special reference to the maturation and differentiation of T-zone histiocytes.     

Immunohistochemical study on cutaneous histioproliferative lesions

Immunohistochemical examinations were performed using five kinds of histiocytic markers [S100 protein, lysozyme, non-specific cross reacting antigen with carcinoembryonic antigen (NCA), alpha 1-antichymotrypsin (alpha 1-ACT) and alpha 1-antitrypsin (alpha 1-AT)] in biopsied tissues from histiocytosis X, juvenile xanthogranuloma, xanthoma tuberosum, xanthoma disseminatum, reticulohistiocytic granuloma and multicentric reticulohistiocytoma, all of which have been classified as histiocytic proliferative disorders. Our results suggested that xanthomatous lesions of the skin to be composed of the histiocytic proliferation of two different cell lineages, i.e. S100+lyso-NCA- T-zone histiocytes and S100-lyso+NCA+ tissue macrophages. Only lesions of histiocytosis X were composed of the former cells. It is suggested that these markers will be useful in determining the delineation of the histiocytic system on the basis of functional heterogeneity.     

Reactive histiocytosis in acute lymphoblastic leukemia and non-Hodgkin's lymphoma

An extensive hemophagocytic syndrome in the termination of one case of pre-T acute lymphoblastic leukemia (ALL) and another case of non-Hodgkin's lymphoma (NHL), are described. Since most of the proliferating cells were mature macrophages and these cells were limited in the mononuclear phagocytic system (MPS), it was determined to be a reactive histiocytosis rather than histiocytic medullary reticulosis (HMR) or malignant histiocytosis (MH). The pathogenesis of the HMR or MH-like syndrome in these patients is discussed, and it is considered that this might be a reaction of the bacterial sepsis related to their immunosuppressed state secondary to the pre-existing malignancies and/or the cytotoxic therapy. The literature was reviewed. Based on a proposal for differential diagnosis between reactive histiocytosis and MH (or HMR), the heterogeneity of HMR-like syndrome complicating the malignancies are clarified.     

Sinus histiocytes in axillary lymph nodes from patients with breast cancer: Macrophage characteristics and activation level

Cell suspensions from 16 tumour-free axillary lymph nodes from breast cancer patients were prepared, using collagenase digestion to free the sinus histiocytes from the fibrous stroma of the nodes. The histiocytic cells so obtained were then characterized using four surface markers: Fc(IgG) receptors, C₃ receptors, DR antigen and a macrophage-associated antigen (defined by the monoclonal antibody VEP-7). In addition phagocytosis was assessed using IgG-coated red cells, and both lysozyme and α-1-antitrypsin were localized by means of immunoperoxidase staining. The results demonstrated that the majority of sinus histiocytes carried surface macrophage markers, but that a minority displayed phagocytosis and the presence of lysozyme or α-1-antitrypsin.     

A study to analyze the origin of tumor cells in malignant fibrous histiocytomas. A multiparametric characterization

To study the derivation of tumor cells of malignant fibrous histiocytomas (MFH), their phenotypical marker profile was investigated and compared with those of malignant histiocytosis (MH) and of different types of soft tissue tumors (STT). The presence of the following markers was investigated: on paraffin sections, alpha-1-antichymotrypsin (ACT); on frozen sections antigens associated with lymphocytes, macrophages and fibroblasts, the enzymes acid phosphatase, nonspecific esterase, and beta-glucuronidase; and, on isolated and cultured cells, the receptors for EA-gamma and complement. Furthermore, the capacity to phagocytose sensitized erythrocytes and carbon particles was studied in vitro. MFH tumor cells and a part of other types of STT shared the expression of ACT and lysosomal enzymes with MH. They differed, however, from MH by the absence of monocyte/macrophage-associated antigens and by the expression of fibroblast-associated antigens, which property they had in common with other STT. MFH tumor cells were not able to form rosettes or to phagocytose Ig-sensitized erythrocytes, but they showed phagocytosis of carbon particles. The results strongly indicate that MFH tumor cells originate from (primitive) fixed mesenchymal cells and are not related to monocyte-derived histiocytes.     

Biology of the human malignant lymphomas. IV. Functional characterization of ten diffuse histiocytic lymphoma cell lines.

Ten consecutive diffuse histiocytic lymphoma (DHL) cell lines established in our laboratory were studied for the presence of Epstein-Barr virus (EBV) genomes, lysozyme, nonspecific esterase and other cytochemical reactions, phagocytic activity, cytoplasmic immunoglobulin light and heavy chains, and surface receptors to sheep erythrocytes, complement, and the Fc fragment of immunoglobulin. In agreement with previous studies performed on biopsy specimens, our results indicate that the diffuse histiocytic lymphomas, as a histopathologic entity, represent a heterogeneous group of neoplasms, the majority of which are B-lymphocyte in origin. The cell lines appear to fall into three categories based on the following criteria: 1) presence of monoclonal cytoplasmic immunoglobulins (B-lymphocytic type, 6/10 cell lines); 2) presence of non-specific esterase, phagocytic activity, and/or lysozyme (histiocytic type, 2/10 cell lines); and 3) absence of all lymphoid and histiocytic cell characteristics (null cell type, 2/10 cell lines). Despite the fact that many of the lymphoma patients had positive serologies to EBV antigens, all of the DHL cell lines were negative for the presence of EBV genomes. Both of the two B-lymphocytic type and one of the two histiocytic type lines tested were susceptible to infection with EBV, as indicated by synthesis of early antigen and also, in a small proportion of the infected cells, of viral capsid antigen. These prototypic DHL cell lines may permit the development of new criteria for the differential diagnosis and treatment of this highly malignant and diverse group of lymphomas.     

True histiocytic lymphoma

It is likely that a significant number of cases of THL will continue to be misdiagnosed unless appropriate cytochemical and immunologic markers are incorporated into the panel of studies performed at diagnosis. The clinical findings are nonspecific. With the possible exception of skin infiltration, the frequency of symptoms and signs appear to approximate those of intermediate grade lymphomas. Most commonly, it is the histopathological features that suggest the histiocytic nature of a malignant process, but these alone are not sufficient to secure the diagnosis. Thus, in the absence of a clearly defined lymphoid origin, it is the detection of specific histiocytic markers that establishes a lymphoma as THL. Only the recognition and careful study of additional cases will potentially enable clinical investigators to identify any unique characteristics and distinguish this disease from other lymphomas. For the present, it would appear that the treatment indicated for a patient with diffuse large cell lymphoma would also be appropriate for a comparable patient with THL. Although long-term disease-free survival in THL is possible, there are presently inadequate data to estimate curability.     

Malignant histiocytosis and related tumors. A clinicopathologic study of 42 cases using cytological, histochemical and ultrastructural parameters

Light and electron microscopical, immunohistochemical and clinical characteristics in 42 cases of malignant neoplasms, arising from true histiocytes, are described. These were separated in a lymphoma-like subtype, called true histiocytic lymphoma (29 patients) and a disseminated variant, called malignant histiocytosis (9 patients). In addition 4 related histiocytic tumors are discussed, including 2 tumors arising from interdigitating cells. Sinus pattern and cytologic features, especially 'window' nuclei, are emphasized as diagnostic criteria. Erythrophagocytosis was not a constant finding. Electron microscopic features, presence of acid phosphatase, acid alpha-naphthylacetate esterase, lysozyme, alpha 1-antitrypsin, alpha 1-antichymotrypsin, Ia-antigen and absence of B- and T-cell markers, were important in establishing the histiocytic nature or excluding a non-histiocytic tumor. A distinct male predominance existed (male:female = 2.5:1) with a higher relapse free period in females (p = 0.032). A high number of mitotic figures appeared to be a favourable sign, p = 0.020 and 0.019, for remission rate and relapse free period respectively. The degree of cell differentiation and the immunohistochemical pattern did not show a correlation with remission and relapse free period. Extranodal involvement and the presence of short profiles of endoplasmic reticulum were prognostically unfavourable signs. True histiocytic lymphomas showed a higher remission rate (p = 0.041) and relapse-free period (p = 0.017) than malignant histiocytosis.     

Macrophage Expression of Interleukin-1 in Lymphoepithelioid Cell (“Lennert's”) Lymphoma

Macrophage activation was studied in three cases of a genuine form of T cell non-Hodgkin's lymphoma particularly rich in epithelioid histiocytes, the so-called “lymphoepithelioid cell lymphoma” or “Lennert's lymphoma”. Host tumor infiltrating macrophages actively produced Interleukin-1 as demonstrated by immunocytochemistry. The activated histiocytes also contained intracytoplasmic tumor cells which were either intact or at various stages of apoptosis. We postulate that in Lennert's lymphoma, tumor cells are capable of activating host macrophages. Initial macrophage activation is followed by IL-1 production with recruitment of additional macrophages accounting for the characteristic histological appearance of this tumor. The activated macrophages are also engaged in a phagocytic antitumoral response. Future studies should investigate if this host response can be potentiated.     

Lymphocyte markers in non-Hodgkin's lymphomas.

The lymphocyte marker pattern of non-Hodgkin's lymphoma cells was related to current concepts of lymphoma classification. In a series of 28 lymphomas lymphocyte markers indicated that 2 were of histiocytic origin, 2 were unclassifiable, none were derived from T cells and the remainder were B-cell neoplasms. The immunoglobulin heavy chain associated with the B-cell tumours was gamma in one case, alpha in one case but was mu in the majority of cases, reflecting the predominance of this heavy chain, together with delta chains, on normal lymph node lymphocytes in man. delta chains accompanied mu chains on the tumour cells in 6/17 lymphomas in which anti-delta staining was performed. delta chains were not found on any lymphomas other than well differentiated diffuse lymphocytic types. There was evidence of a reduction in surface immunoglobulin, Fcgamma and C3 receptors on undifferentiated lymphoma cells. T lymphocytes of normal morphology were present in all lymphomas except one, and were more numerous in follicular lymphomas than in diffuse tumours.     

MALIGNANT HISTIOCYTOSIS: A STUDY ON CLINICOPATHOLOGICAL FEATURES AND CELL ORIGIN

Thirty- one autopsy cases previously diagnosed as malignant histiocytosis (MH) were studied by means of immunohistochemical staining. Antibodies detecting the formalin resistant epitopes on T- cells, B- cells and those of histiocyte/monocyte origin were used. It was shown that the malignant histiocytes reacted only to the cell markers derived from histlocyte/monocyte. and only a part of lymphocytes showed positive reaction to the T and B cell markers. It is suggested that the histiocyte/monocyte lineage is the possible origin of the malignant proliferating cells in MH. The clinicopathological features and the differentiation of MH from familial erythrophagocytic lymphohistiocytosis, virus-associated hemophagocytic syndrome and malignant lymphoma are described. The pathogenesis. the causes of death and the points for attention in the treatment of MH are also discussed.     

Heterogeneity of cloned cell lines established from a transplantable rat malignant fibrous histiocytoma.

Four cloned cell lines, MT-7, MT-8, MT-9 and MT-10, were established from a transplantable malignant fibrous histiocytoma (MFH) of F344 rats to investigate the histogenesis of the tumor. Cells of MT-7, MT-9 and MT-10 had fine structures characteristic of histiocytes, such as numerous cell processes, many lysosomes and well-developed cytoplasmic organelles. They stained positively for histiocytic lysosomal and antigenic markers. In addition, MT-9 cells contained microfilaments and well-developed RER in their cytoplasm, suggesting that they may be facultative fibroblasts. MT-8 cells stained weakly for histiocytic markers and had scant cytoplasmic organelles. They were identified as undifferentiated mesenchymal cells. The tumors induced in syngeneic rats by inoculating MT-7 or MT-10 consisted of a mixture of the pleomorphic, myxoid and storiform types of MFH, and those by MT-9 were of the storiform type. Cells forming these tumors stained positively for histiocytic markers. Tumors induced by MT-8 consisted of undifferentiated cells negative to these stainings. The histogenesis of MFH is surmised to be related to various differentiation stages shifting from undifferentiated cells to histiocytic cells capable of acting as facultative fibroblasts.     

Heterogeneity of Cloned Cell Lines Established from a Transplantable Rat Malignant Fibrous Histiocytoma

Four cloned cell lines, MT-7, MT-8, MT-9 and MX-10, were established from a transplantable malignant fibrous histiocytoma (MFH) of F344 rats to investigate the histogenesis of the tumor. Cells of MT-7, MT-9 and MT-10 had fine structures characteristic of histiocytes, such as numerous cell processes, many lysosomes and well-developed cytoplasmic organelles. They stained positively for histiocytic lysosomal and antigenic markers. In addition, MT-9 cells contained microfllaments and well-developed RER in their cytoplasm, suggesting that they may be facultative fibroblasts. MT-8 cells stained weakly for histiocytic markers and had scant cytoplasmic organelles. They were identified as undifferentiated mesenchymal cells. The tumors induced in syngeneic rats by inoculating MT-7 or MT-10 consisted of a mixture of the pleomorphic, myxoid and storiform types of MFH, and those by MT-9 were of the storiform type. Cells forming these tumors stained positively for histiocytic markers. Tumors induced by MT-8 consisted of undifferentiated cells negative to these stainings. The histogenesis of MFH is surmised to be related to various differentiation stages shifting from undifferentiated cells to histiocytic cells capable of acting as facultative fibroblasts.     

Bone Marrow Findings in Malignant Histiocytosis and/or Malignant Lymphoma with Concurrent Hemophagocytic Syndrome

We examined bone marrow specimens from 19 patients with malignant histiocytosis (MH) and/or malignant lymphoma (ML) with concurrent hemophagocytic syndrome (HS) who suffered from high fever, hepatosplenomegaly, liver dysfunction, profound cytopenia, and erythrophagocytosis. There was little lymph-node enlargement or no tumor formation. The neoplastic cells in 3 patients exhibited histiocytes/macrophages phenotype with positive reactions for fluoride-sensitive nonspecific esterase, lysozyme and CD68 (KP1). Twelve other patients showed a T-cell (CD3) phenotype, in which 5 patients expressed CD30 (BerH2) as well. B-cell characteristics with CD20 (L26), CIg. νλ and γκ were manifest in 2 patients, but indeterminate markers were found in the 2 remaining patients. Eighteen patients showed an infiltration of large neoplastic cells mainly with noncohesive interstitial growth pattern, ranging from 1.7% to 74.2% of the nucleated cells in the bone marrow. A large number of histiocytes/macrophages and dendritic cells was diffusely observed in 15 patients. Severely decreased hematopoiesis in all three series of hematopoietic cells was found in 16 patients.

Bone marrow infiltration by the neoplastic cells and numerous reactive cells with erythrophagocytosis appears be an important factor of profound cytopenia in patients of MH and/ or ML with HS. The infiltrating pattern of the neoplastic and reactive cells in the bone marrow of MH and/or ML with HS was different from that of other types of peripheral T-cell ML, B-cell ML in high grade malignancy, and Hodgkin's disease. Cell characteristics and lineage of the neoplastic cells in MH and/or ML with HS are also discussed in this study.     

True Histiocytic Lymphoma: A Study of 12 Cases Based on Current Definition

True histiocytic lymphoma (THL), as it is currently defined, is a rare entity. We report 12 cases of THL seen at Stanford over the last ten years. By definition, the neoplastic cells in each case showed histological and immunological evidence of histiocytic differentiation. Seven females and five males ranged in age from 9 to 67 years. Sites of involvement included lymph node, soft tissue, bone, stomach, small intestine, mediastinum, kidney, breast and salivary gland. Lymph nodes showed diffuse architectural effacement and/or a paracortical pattern of involvement. The infiltrates involved other tissues in a diffuse pattern. Cytologically the cells were characterized by abundant eosinophilic cytoplasm and enlarged, indented eccentrically placed nuclei containing prominent nucleoli. In all cases the cytological features were sufficiently atypical to indicate a neoplastic infiltrate. Paraffin section immunophenotyping demonstrated reactivity of the atypical cells for CD15, 43, 45RO, 45RB, 68, lysozyme and/or S100. In frozen sections, the atypical cells demonstrated reactivity for CD4 (cytoplasmic), 11c, 14, 15, and/or 68. Genotypic studies were performed on 3 cases, one of which showed rearrangements of immunoglobulin heavy and light chain genes. Follow-up was available on eleven patients, six of whom died of disease 0.5 to 36 months following diagnosis.     

Morphology and immunohistochemistry of true histiocytic lymphoma--report of 4 cases

True histiocytic lymphoma (THL) is a rare malignancy of histiocyte. It is difficult to diagnose by light microscopy alone. In this paper, 4 cases of THL were reported basing on light and electron microscopic examination, and immunohistochemical study. Histiocytic lymphoma was of Langerhans cell origin in one case and of interdigitating reticulum cell origin in the other. The other 2 patients probably belonged to neoplasm of macrophage or dendritic reticulum cell origin. The differential diagnosis between the true histiocytic lymphoma and other tumors or diseases was briefly discussed.     

The new World Health Organization classification of lymphomas: the past, the present and the future.

The REAL Classification of lymphomas, proposed in 1994, represents a new paradigm in lymphoma classification, consisting of a list of biologic entities defined by clinicopathologic and immunogenetic features. The non-Hodgkin's lymphomas comprise precursor lymphoblastic and mature cell neoplasms of B, T or putative natural killer cell lineage. An individual entity can exhibit a range of morphologic appearances and a range of clinical behavior. The categories in Hodgkin's lymphomas are identical to the widely used Rye classification except for the additional of a new category termed 'lymphocyte-rich classical Hodgkin's lymphoma'. The REAL classification has been validated by a major multi-institutional study involving 1378 cases (The Non-Hodgkin's Lymphoma Classification Project), showing that it is both reproducible and clinically relevant. The new World Health Organization classification of hematopoietic and lymphoid tumors, to be published in 2001, is a joint project of the Society for Hematopathology and European Association of Hematopathologists, under the auspices of the World Health Organization. This classification includes not only lymphoid neoplasms, but also myeloid, histiocytic and mast cell neoplasms. The lymphoma component of the classification is merely an update of the REAL classification, with minor changes necessitated by new information that has become available since its proposal. A conceptual grouping of the non-Hodgkin's lymphomas into four categories (indolent, aggressive, highly aggressive, and localized indolent) is also presented in this review. The next major impetus influencing the approach to lymphoma classification will no doubt be molecular genetics, in particular DNA microarrays, which will yield an enormous amount of new data that will aid in the understanding of lymphomas.     

Histiocytic neoplasias: immunohistochemical evaluation of their frequencies among malignant lymphoma and related conditions in Japan

Through histologic review of 1,766 cases with malignant lymphoma and related conditions, 35 cases (2%) were selected as probable histiocytic neoplasias. Proliferating cells in these cases had voluminous, granulated cytoplasm, and round to irregularly shaped nuclei often with bi- or multinucleated forms showing monomorphous or polymorphous proliferation accompanying small lymphocytes, plasma cells, and, less frequently, eosinophils. Cases showing proliferation of convoluted cells with numerous benign-appearing histiocytes or large cells with clear cytoplasm were excluded under a diagnosis of T-cell lymphoma. To evaluate the immunologic character of proliferating cells, immunohistochemistry using antibodies Mx-Pan B, MB-1, MT-1, UCHL-1, lysozyme, alpha 1-antitrypsin, alpha 1-antichymotrypsin, S-100 alpha, S-100 beta, Leu M1, epithelial membrane antigen, and Ki-1 were carried out in 23 cases. Naphthol-ASD-chloracetate reaction and toluidine blue stain were also performed. These procedures revealed that 12 cases (52%) were B-cell type, three cases (13%) T-cell type, six cases (26%) true histiocytic type, and two cases null type. Therefore, the frequency of cases with true histiocytic neoplasias among cases with malignant lymphoma and related conditions in Japan may be 0.5%.