Virus-associated hemophagocytic syndrome: a benign histiocytic proliferation distinct from malignant histiocytosis

Hematologic abnormalities in the acquired immune deficiency syndrome

Blood and marrow specimens were evaluated from 12 patients with the acquired immune deficiency syndrome (AIDS). Ten patients were anemic, eight leukopenic, and three thrombocytopenic. Pancytopenia was present in two patients and subsequently developed in two others. Reticulocyte counts were not increased in the anemic patients. The most common peripheral blood abnormalities were a left shift in the granulocyte series, lymphopenia, atypical lymphocytes, and vacuolated monocytes. Marrow cellularity was increased in five patients and reduced in three. Marrow reticulin was increased in 10 patients; in three of these, marrow could not be obtained by aspiration. Plasma cells were increased in number in every marrow aspirate, and there was a left shift in the myeloid series in most. Aggregates of atypical lymphocytes or a diffuse increase in marrow lymphocytes occurred in seven patients. An increase in histiocytes was observed in seven marrow aspirates; in five of these, the histiocytes were phagocytizing red cells, white cells, and platelets. Necrosis was present in four marrow specimens. These hematologic abnormalities reflect, in part, the presence of systemic infection, inflammation, and the inanition associated with them. However, the high incidence of myelofibrosis, alterations in marrow cellularity, pancytopenia, and hematophagic histiocytosis indicates that the bone marrow is a target organ in AIDS.

Malignant histiocytosis: a clinical, histologic, and immunohistochemical study of 20 cases

To better characterize the diagnostic criteria and clinical behavior of malignant histiocytosis, 20 patients treated at the Mayo Clinic during a 25-year period were studied. A wide spectrum of cytologic differentiation was observed, with cells ranging from bland to highly anaplastic; hemophagocytosis was prominent only in conjunction with a bland histologic appearance. In surgical specimens, the diagnosis of malignant histiocytosis necessitated the use of immunoperoxidase methods for lysozyme, immunoglobulin light chain, and alpha-antitrypsin content, as well as cytochemical stains for acid phosphatase and nonspecific esterase. All autopsies showed that organ involvement had varied somewhat from that reported earlier. The correct diagnosis of malignant histiocytosis was made prior to death in only ten of the 20 cases. The mean survival in the 17 fatal cases was 7.6 months; three of the seven patients treated by aggressive chemotherapy achieved complete remission. Relatively longer survival was correlated with initial confinement to the skin and the absence of cytopenia or liver function abnormalities. Three patients with pulmonary involvement from malignant histiocytosis had apparent inappropriate antidiuretic hormone secretion in the absence of central nervous system disease. The accelerated clinical progression of malignant histiocytosis and its response to current chemotherapeutic regimens make rapid diagnosis and familiarity with the pathologic variations seen in this disorder imperative. Routine utilization of special light-microscopic and immunohistochemical stains is mandatory.

Impaired natural killer activity in lymphohistiocytosis syndrome

In six patients with well-documented lymphohistiocytosis syndrome, natural killer activity was found to be profoundly impaired and could not be increased by incubation in vitro with interferon. This abnormality was not found in parents of the affected children. A clear correlation with the activity of the disease was observed, although a delay of a few weeks (possibly reflecting the life span of NK cells in blood) was seen in the disappearance of NK activity after the onset of the disease and its reappearance after remission. No absolute correlation was observed between NK activity and percentage of leukocytes detected by the Leu-7 monoclonal antibody. Our findings indicate that testing NK activity is useful for the diagnosis of lymphohistiocytosis syndrome and can be used as an index of activity of the disease, among other major clinical and biologic signs of this syndrome. Reversal of the NK activity defect (rather than detection of Leu-7 positive cells) appears to be a good criterion of complete remission.

Virus-associated hemophagocytic syndrome due to Epstein-Barr virus

The clinical and autopsy findings in a case of virus-associated hemophagocytic syndrome in a previously healthy 17-year-old girl are presented. Serum titers to Epstein-Barr viral antigens were unusually elevated. In addition to widespread proliferation of hemophagocytic histiocytes and lymphoid depletion, there were areas of non-suppurative necrosis in lymph nodes and spleen, which have not been previously reported.

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.

Malignant histiocytosis in childhood: morphologic considerations

Eight cases diagnosed over a ten-year period as malignant histiocytosis (MH; histiocytic medullary reticulosis) were reviewed to clarify diagnostic criteria for the childhood disease and to identify sources of diagnostic confusion. Five of the eight cases met the authors' criteria for diagnosis; i.e., they were characterized by loose mixed infiltrates composed of three cell types--well-differentiated histiocytes, prohistiocytes, and malignant histiocytes--and they had no leukemic phase. Three cases did not share these features and were reclassified. The liver was found to be the organ most useful in premortem diagnosis, and immunoperoxidase staining for immunoglobulins and lysozyme was also helpful. The clinical and morphologic features of the five cases confirm the authors' view that diagnoses of MH should be limited to cases in which there is a loose pleomorphic population of all three types of histiocytes and that cases with monomorphous populations of aggregated malignant cells should be classified as lymphomas.

Malignant histiocytosis

The clinical features, therapy, and hospital course of ten consecutive patients with malignant histiocytosis (MH) are presented. The value of bone marrow aspiration for the diagnosis is discussed. The patient's performance status as described in this report by the organ dysfunction score may predict survival and response to chemotherapy. The literature on chemotherapy in this disease is reviewed. Combination chemotherapy may be the best approach to treatment, but there is little experience with single agents. There is a great need for better characterization of the malignant cell in this disorder.

Malignant lymphoma and erythrophagocytosis simulating malignant histiocytosis

Six patients with malignant lymphoma are described, in whom a syndrome that mimicked malignant histiocytosis clinically and pathologically developed as a terminal event. The clinical course was characterized by hepatosplenomegaly, fever, and a rapid fall in all hematologic counts. Survival from onset of this syndrome was less than six weeks. Pathologically, activation of benign histiocytes with marked erythrophagocytosis was seen throughout the reticuloendothelial system. Disseminated lymphoma was also evident but was grossly and microscopically segregated from the erythrophagocytic process. Immunologic and cytochemical studies in two cases indicated the lymphomas to be of peripheral T cell origin, whereas the phagocytic cells had markers characteristic of histiocytes. A likely mechanism for this syndrome is the production of lymphokines (macrophage-activating factors) by neoplastic T lymphocytes.

Malignant histiocytosis. Clinical and cytogenetic studies in a newborn and a child

Malignant histiocytosis (MH) was diagnosed on the cytologic and cytochemical features of the malignant cells present in bone marrow smears from an infant and a child. The diagnosis of MH was confirmed by light and electron microscopic studies on bone marrow and skin biopsy specimens, and bone marrow and liver biopsy specimens, respectively. Both patients showed a deterioration while receiving prednisone monotherapy, but they responded well to a combination of vincristine and cyclophosphamide. The infant has remained disease-free for 52+ months now, but the child died of a relapse 11 months after diagnosis. Cytogenetic studies of blood and/or bone marrow cells were performed before treatment. In the infant, a pathologic cell line with a translocation t(8;16)(p11;p13) was found; this abnormality was no longer present after remission was obtained. In the second patient, a hyperdiploid cell line with major karyotypic anomalies was found. When studied in relapse and shortly before death, additional chromosomal abnormalities were seen. The data from this study show that prednisone should be used with caution in MH, and that it should be omitted from combination chemotherapy when adverse effects are noted during short-term monotherapy. Also, cytogenetic studies should be performed more often in MH to determine the significance and possible nonrandomness of chromosomal abnormalities in this disease.

Familial hemophagocytic lymphohistiocytosis

Familial hemophagocytic lymphohistiocytosis (FHL) is probably a genetically transmitted disease affecting infants and very young children. Cardinal symptoms are fever, hepatosplenomegaly, and pancytopenia. Frequently meningeal involvement is seen, manifested by neurologic symptoms and a lymphohistiocytic pleocytosis with increased protein levels in the cerebrospinal fluid. Characteristic laboratory findings in FHL are hypertriglyceridemia and hypofibrinogenemia, which are reversible with treatment. The disease has been rapidly fatal in most patients, but recently longterm remissions have been achieved with cytotoxic agents. Pathohistologic examination shows a widespread infiltrate of lymphocytes and mature macrophages with prominent hemophagocytosis affecting especially liver, spleen, lymph nodes and the central nervous system. Atrophy of the lymphatic tissue is a common finding. From the histologic picture FHL has to be grouped among the histiocytoses of reactive origin since the cells involved show no signs of malignancy. The etiology and pathogenesis of FHL are not known at present. Immunologic studies present evidence for a disturbed function of T lymphocytes, but a secondary immune defect seems to be more likely than primary immune deficiency. Among the broad clinical spectrum of histiocytic disorders especially histiocytic reactions due to infection, histiocytosis X and malignant histiocytosis have to be considered in the differential diagnosis of FHL.

Complete recovery of histiocytic medullary reticulosis-like syndrome in a child with acute lymphoblastic leukemia

A 6-year-old boy with acute lymphoblastic leukemia (ALL) developed a haemophagocytic syndrome resembling histiocytic medullary reticulosis (HMR) but made a complete recovery on supportive treatment. This was subsequently found to have been associated with a parainfluenzal infection. It is suggested that HMR in immunocompromised hosts may represent a reactive process to an opportunistic viral infection and that the use of chemotherapy in these patients may be deleterious.

Giant cell granulomatosis of lymph nodes with a fatal course

We report two examples of an unusual expression of fatal granulomatosis with primary lymph node location, characterized histologically by numerous giant cells of the Langhans' type, effacement of the nodal structure, mixed lymphohistiocytic infiltrate, and marked histiocyte cell maturity, all features which initially did not exclude the possibility of a granulomatous process of infectious origin. The clinical features of these cases include cellular or combined immunodeficiency, a possible family history and a rapidly fatal course. The present article emphasizes the great similarity which can exist between histiocytic and granulomatous disorders, the great variability of histiocytic diseases from the pathological view-point, the presence of borderline examples, and the several overlapping features of different entities. Specifically, the most remarkable finding of these two cases is the existence of numerous mature giant cells of the Langerhans' type within a massive obliteration of the nodal structure. Furthermore, these giant cells characterized by a strikingly orderly disposition of peripheral nuclei in a wreath-like pattern, frequently suggesting the structure of Touton's giant cells.

Infectious mononucleosis fifty years after the discovery of the Paul-Bunnell test

The Paul-Bunnell test, now 50 years old, is still of fundamental importance in the diagnosis of infectious mononucleosis, even though various immunologic methods have been developed in clinical practice to identify constituents of the Epstein-Barr virus (EBV). The demonstration of sheep red cell agglutinins in infectious mononucleosis (Paul-Bunnell) was in fact the first observation of the presence of heterophil antibodies in this viral disease which was later shown to evoke a polyclonal antibody response to a wide spectrum of autoantigens as well. The selective tropism of EBV for B lymphocytes and the reactivity of T lymphocytes to these infected B lymphocytes are the pathophysiological elements characteristic of infectious mononucleosis, and are the reason for this massive antibody response.

Cutaneous malignant histiocytosis: a clinical and histopathologic study of eight cases, with immunohistochemical analysis

Eight cases of autopsy-proved malignant histiocytosis (MH) are reported, in which cutaneous involvement was a prominent finding at initial clinical presentation. In two patients, the disease remained confined to the skin for significant periods before systemic dissemination appeared. Immunohistochemical analysis of cutaneous infiltrates of MH showed uniform negativity of the atypical cells for lysozyme, immunoglobulin light chain, glycogen, and chloroacetate esterase content. In five cases, cytochemical stains for acid phosphatase, butyrate (nonspecific) esterase, chloroacetate esterase, and peroxidase activity were performed on bone marrow aspirates containing malignant cells; all demonstrated diffuse positivity for acid phosphatase and nonspecific esterase, and negativity for peroxidase and chloroacetate esterase. Touch-imprint preparations of cutaneous lesions in one of these cases yielded identical results. These findings indicate that cytochemical methods are preferable to immunohistochemical technics in identification of histiocytic malignancies and that foci of skin involvement may provide a useful source for such diagnostic evaluation.

Spontaneous regression of congenital cutaneous histiocytosis X: report of a case with discussion of nosology and pathogenesis

Spontaneous regression of histiocytosis X is a rare biologic event as judged by the extensive recorded experience in the literature. We present a case of congenital cutaneous histiocytosis X that resolved without specific therapy in the first week of life. Histologic and ultrastructural studies confirmed the interpretation. This child is an example of so-called pure cutaneous histiocytosis, which, like the other unisystem forms of the disorders, has an excellent prognosis.

Chronic recurrent demyelinating encephalomyelitis associated with hemophagocytic lymphohistiocytosis

A man aged 31 with remittent fever, leukopenia, polyuria, and splenomegaly in addition to chronic and recurrent episodes of neurologic abnormalities was examined pathologically. A chronic type of perivenous encephalomyelitis was found in the CNS, and chronic inflammatory lesions were noticed in the infundibulo-hypophyseal system and also in the peripheral nerves. Moreover, hemophagocytic lymphohistiocytosis predominated in the reticuloendothelial system. This seemed to be the first adult case of demyelinating disease with hemophagocytic lymphohistiocytosis.

Pseudolymphomas of the stomach: a lesion characterized by progressively transformed germinal centres

Pseudolymphomas of the stomach are frequently associated with chronic peptic ulcer. Out of the 11 cases studied, there were characteristic pathohistological signs of chronic ulceration in eight and suspicion of chronic ulcer in three. Thus it seems that pseudolymphomas frequently represent an exaggerated lymphocytic reaction to chronic ulcer. The pseudolymphomatous reaction is essentially a follicular hyperplasia with the gradual development of progressively transformed germinal centres. These large nodular structures are usually found in the submucosa and, at first inspection, the transformed follicle can easily be mistaken for a possibly malignant diffuse lymphomatous lesion. However, once the existence of the condition is realized, its recognition by the pathologist should be easy. A heavy plasma cell infiltration of polytypic immunoglobulin type associated with progressively transformed germinal centres might be a consequence of long-standing antigenic stimulation.

Wiskott-Aldrich syndrome: histopathologic findings in the lymph nodes and spleens of 15 patients

Seventeen lymph nodes and 13 spleens from 15 patients with the Wiskott-Aldrich syndrome were examined histologically. The material included both biopsy and autopsy specimens. Consistent findings included depletion of small lymphocytes from T cell areas (all cases), prominence of the reticulum cell stroma (all cases), the presence of atypical plasma cells with and without plasmacytosis (16 lymph nodes and 11 spleens), and extramedullary hematopoiesis (13 lymph nodes and 9 spleens). Less frequent features noted were tissue eosinophilia, hemophagocytosis, focal fibrosis, and progressive depletion of germinal centers. One case with a unique abundance of transformed lymphocytes is described.

Familial erythrophagocytic lymphohistiocytosis in infancy

A 2 1/2-month-old infant suffering from pyrexia, purpura, hepatosplenomegaly, pancytopenia and hyperlipidemia is reported. Liver and spleen biopsies revealed mononuclear histiocytic infiltration with marked erythrophagocytosis. The girl died at 7 1/2 months of age. Her brother died in infancy with an analogous clinical picture. The parents were first cousins. The clinical presentation and laboratory findings are consistent with the diagnosis of familial erythrophagocytic lymphohistiocytosis.

Cytophagic histiocytic panniculitis with fever, cytopenia, liver failure, and terminal hemorrhagic diathesis

We have seen five adult patients with a clinical picture of recurrent histiocytic, cytophagic panniculitis, cytopenia, abnormal liver function tests, and a terminal, febrile bleeding diathesis. Originally thought to have Weber-Christian disease, these patients, we believe, represent a unique syndrome: lobular, histiocytic, cytophagic panniculitis. Erythrophagocytosis and cytophagocytosis are readily observed, but the cells do not show malignant features. Histiocytosis can be found at times in the bone marrow, lymph nodes, liver, spleen, and serosal tissues, as well as in the skin and subcutaneous tissues. The terminal hemorrhage in these patients is characterized by features of pancytopenia, liver failure, and intravascular coagulation. This disease may be separated from malignant histiocytosis by the chronic course, the primary involvement of the adipose tissue, and the benign histiocytes in the infiltrate. It has some similarities to other regional histiocytoses such as sinus histiocytosis, intestinal histiocytosis, and splenic histiocytosis.

Phagocytosis of neutrophils by marrow macrophages in childhood chronic benign neutropenia

Chronic benign neutropenia of childhood is a heterogeneous disorder. This study describes two severely neutropenic children with a benign clinical course and the unique bone marrow finding of macrophage engulfment of band and segmented neutrophils. Phagocytic vacuoles in the majority of macrophages contained neutrophils in various stages of digestion at both the light and electron microscope level (with as many as four neutrophils observed in single macrophages). Ultrastructural studies demonstrated that the neutrophils were morphologically normal, and apparently viable at the time of phagocytosis. This type of neutrophil phagocytosis was not observed in five other consecutively studied children with CBN. All of these children with CBN had ultrastructurally normal neutrophils, lacked demonstrable antineutrophil antibodies or serum inhibitors to in vitro myelopoiesis, and had normal colony-forming cells and colony-stimulating activity in vitro. Thus despite many similar clinical and laboratory features in children with CBN, only a unique subgroup of these patients demonstrates abnormal neutrophil-macrophage interaction.

Atypical lymphadenopathies of the head and neck

Atypical lymphadenopathies fail to achieve the morphologic criteria of a malignant neoplasm, but exceed the usual concepts of follicular, lymphoid, or sinus histiocytic hyperplasias. Rich cellular proliferations usually composed of prominent histiocytes, or immunoblasts, or both with or without a vascular scaffolding obscure the nodal architecture. Toxoplasmosis, infectious mononucleosis, zoster, and vaccination-induced lymphadenopathies are caused by infectious agents, dermatopathic lymphadenitis is associated with cutaneous disease, anticonvulsant pseudolymphoma occurs in individuals hypersensitive to anticonvulsants (usually phenytoin), and Chediak-Higashi syndrome is an inherited abnormality of lysosomal microtubule function; the causes of sinus histiocytosis with massive lymphadenopathy, giant lymph node hyperplasia, angioimmunoblastic lymphadenopathy, mucocutaneous lymph node syndrome, and this histiocytoses remain unknown. The clinical course of these abnormalities varies from self-limited acute diseases (viral lymphadenopathies, toxoplasmosis, dermatopathic lymphadenitis, and usually anticonvulsive lymphadenopathy) to protracted, but benign abnormalities (sinus histiocytes with massive lymphadenopathy, giant lymph node hyperplasia, and multifocal eosinophilic granuloma). The diagnosis of angioimmunoblastic lymphadenopathy, Chediak-Higashi syndrome, and mucocutaneous lymph node syndrome necessitates a guarded prognosis, for death or the advent of a malignant lymphoma may interrupt their clinical course. Acute disseminated histiocytosis, even though the proliferated cell lacks the cytologic criteria of malignancy, should be regarded and treated as a malignant neoplasm.

Histiocytic medullary reticulosis complicating chronic lymphocytic leukaemia: malignant or reactive?

We describe 4 patients with a haemophagocytic syndrome resembling histiocytic medullary reticulosis (HMR) complicating chronic lymphocytic leukaemia (CLL) of 9 months to 8 years duration. Surface marker studies in 2 cases showed that the CLL lymphocytes were of B-cell type in one and of T-cell type in the other. 2 of the patients had histiological evidence of co-existing immunoblastic sarcoma at the time of diagnosis of the HMR-like syndrome and all 4 patients died within 3 weeks of this diagnosis. The pathogenesis of the HMR-like syndrome in these patients is discussed and it is concluded that it is probably reactive to an underlying opportunistic viral function related to their immunodepressed state secondary to CLL and/or the cytotoxic therapy.

Demyelination with hemophagocytic lymphohistiocytosis of the CNS

A case of hemophagocytic lymphohistiocytosis with central nervous system involvement in an infant is presented. Marked demyelination of cerebral and cerebellar white matter is associated with an intense histiocytic infiltrations and astrogliosis. Histiocytes phagocytic of erythrocytes and lymphocytes are noted in a meningeal, subependymal, and perivascular distribution. Severe depletion of lymphoid tissue, associated with histiocytic infiltration, is also seen in multiple organs. While the etiology of this disease is unknown, alterations in the immune response and possible viral relationships are explored.

Familial lymphohistiocytosis

Familial lymphohistiocytosis is a genetically transmitted disease affecting infants and very young children with usually a fatal outcome. Cardinal symptoms are fever, hepatosplenomegaly, and pancytopenia. Histologic examination shows infiltration of all organs with phagocytosing histiocytes and lymphocytes as well as atrophy of the normal lymphoid tissue. The distinction from other histiocytic disorders, i.e., Letterer-Siwe disease or malignant histiocytosis, may be difficult. However, the familial occurrence and characteristic findings in the coagulation system and lipid pattern make familial lymphohistiocytosis a sufficiently distinct clinical entity. This report review 79 cases fron the literature and adds four of own observations.

Legionnaires' disease

Described here is a unique case of Legionnaires' disease in a previously healthy 46 year old man in whom disseminated disease was demonstrated in the kidneys, bone marrow, spleen and multiple peripheral lymph nodes at autopsy. The pathologic distribution of the lesions suggests that dissemination occurred by both hematogenous and lymphatic pathways. Pancytopenia associated with bone marrow destruction and fibrosis suggests that substances toxic to hematopoietic cells were present. It is likely that many of the unusual systemic manifestations of this disease are related to dissemination of the bacterium. The findings presented extend the spectrum of the clinical and pathologic manifestations of Legionnaires' disease from a mild and self-limited illness to a severe and fatal disseminated form of the disease.

Thrombocytopenia in children

Thrombocytopenia in children can be classified on the basis of understanding of the production, life span, and fate of platelets. Thrombocytopenia may be familial, associated with drug-ingestion as a result of immune mediated mechanisms, direct toxicity to circulating platelets, or injury to megakaryocytes, or associated with other disease states.