Intratumoral Canine Distemper Virus Infection Inhibits Tumor Growth by Modulation of the Tumor Microenvironment in a Murine Xenograft Model of Canine Histiocytic Sarcoma

Histiocytic sarcomas refer to highly aggressive tumors with a poor prognosis that respond poorly to conventional treatment approaches. Oncolytic viruses, which have gained significant traction as a cancer therapy in recent decades, represent a promising option for treating histiocytic sarcomas through their replication and/or by modulating the tumor microenvironment. The live attenuated canine distemper virus (CDV) vaccine strain Onderstepoort represents an attractive candidate for oncolytic viral therapy. In the present study, oncolytic virotherapy with CDV was used to investigate the impact of this virus infection on tumor cell growth through direct oncolytic effects or by virus-mediated modulation of the tumor microenvironment with special emphasis on angiogenesis, expression of selected MMPs and TIMP-1 and tumor-associated macrophages in a murine xenograft model of canine histiocytic sarcoma. Treatment of mice with xenotransplanted canine histiocytic sarcomas using CDV induced overt retardation in tumor progression accompanied by necrosis of neoplastic cells, increased numbers of intratumoral macrophages, reduced angiogenesis and modulation of the expression of MMPs and TIMP-1. The present data suggest that CDV inhibits tumor growth in a multifactorial way, including direct cell lysis and reduction of angiogenesis and modulation of MMPs and their inhibitor TIMP-1, providing further support for the concept of its role in oncolytic therapies.

Histiocytic Sarcoma with p16-Overexpression Presenting as Uterine Cervical Mass

A 67-year-old woman presented with post-menopausal bleeding. Physical examination and imaging revealed a cervical mass with extensive pelvic involvement and supraclavicular lymphadenopathy. Clinical diagnosis was stage IVB cervical carcinoma. Cervical biopsy revealed high-grade squamous intraepithelial lesion and epithelioid tumor cells in the stroma. Lymph node biopsy revealed metastasis by similar epithelioid tumor cells. The epithelioid tumor cells were positive for p16, CD68, and CD163 on immunohistochemical study. The diagnosis of histiocytic sarcoma (HS) was rendered. This case demonstrated a rare presentation of HS mimicking cervical carcinoma. Awareness of this rare entity with appropriate ancillary tests is essential for accurate diagnosis. In contrast to the previous postulation of p16-inactivation as the pathogenesis of HS, p16-overexpression might suggest a different pathway for tumorigenesis.

Syndrome of inappropriate antidiuretic hormone secretion in a dog with a histiocytic sarcoma

A 7-year-old female neutered Bernese mountain dog was presented in a semi-comatose state. Based on serum hypo-osmolality with inappropriate urine hyper-osmolality and urine sodium excretion, the dog was diagnosed with a syndrome of inappropriate antidiuretic hormone secretion secondary to a histiocytic sarcoma. This report describes the first case of this syndrome in a dog with histiocytic sarcoma.

In vitro action of flavonoids in the canine malignant histiocytic cell line DH82

Cancer is commonly diagnosed in dogs over the age of 10 and is a leading cause of death due to the lack of effective drugs. Flavonoids possess antioxidant, anti-inflammatory and anticarcinogenic properties and have been studied as chemopreventive agents in human cancer therapy. However, the literature on dogs is sparse. In this study, we analyzed the effect of nine flavonoids on cell viability, DNA damage and topoisomerase IIa/IIb gene expression in a canine tumor cell line (DH82). Apigenin, luteolin, trans-chalcone and 4-methoxychalcone showed the highest degree of cytotoxicity in the absence of considerable DNA damage, whereas genistein exhibited low cytotoxicity but induced a high level of DNA damage. These five flavonoids inhibited topoisomerase IIa and IIb gene expression to variable extents and with variable specificity. Genistein exerted a lower inhibitory effect on the two topoisomerases than luteolin and apigenin. trans-Chalcone and 4-methoxychalcone exerted greater inhibition of topoisomerase IIa expression than topoisomerase IIb. The differences in the effects between genistein and luteolin and apigenin might be explained by the position of ring B, whereas the more specific effect of chalcones on topoisomerase IIa might be due to their open chain structure.

Inhibition of survivin influences the biological activities of canine histiocytic sarcoma cell lines

Canine histiocytic sarcoma (CHS) is an aggressive malignant neoplasm that originates from histiocytic lineage cells, including dendritic cells and macrophages, and is characterized by progressive local infiltration and a very high metastatic potential. Survivin is as an apoptotic inhibitory factor that has major functions in cell proliferation, including inhibition of apoptosis and regulation of cell division, and is expressed in most types of human and canine malignant neoplasms, including melanoma and osteosarcoma. To investigate whether survivin was expressed at high levels in CHS and whether its expression was correlated with the aggressive biological behavior of CHS, we assessed relation between survivin expression and CHS progression, as well as the effects of survivin inhibition on the biological activities of CHS cells. We comparatively analyzed the expression of 6 selected anti-apoptotic genes, including survivin, in specimens from 30 dogs with histiocytic sarcoma and performed annexin V staining to evaluate apoptosis, methylthiazole tetrazolium assays to assess cell viability and chemosensitivity, and latex bead assays to measure changes in phagocytic activities in 4 CHS cell lines and normal canine fibroblasts transfected with survivin siRNA. Survivin gene expression levels in 30 specimens were significantly higher than those of the other 6 genes. After transfection with survivin siRNA, apoptosis, cell growth inhibition, enhanced chemosensitivity, and weakened phagocytic activities were observed in all CHS cell lines. In contrast, normal canine fibroblasts were not significantly affected by survivin knockdown. These results suggested that survivin expression may mediate the aggressive biological activities of CHS and that survivin may be an effective therapeutic target for the treatment of CHS.

Primary histiocytic sarcoma of the stomach: A case report with imaging findings

Histiocytic sarcoma (HS) is a rare malignant neoplasm that originates from a histiocytic hematopoietic lineage characterized by histiocytic differentiation and its corresponding immunophenotypic features. We herein reported a case of primary HS of the stomach which was confirmed through histopathologic examination and immunohistochemical staining. A 52-year-old woman presented with progressive difficulty in feeding and dull pain in the epigastric region. Gastroscopy, endoscopic ultrasonography, double contrast examination, and computed tomography revealed a mass located on the posterior wall of fundus and lesser curvature of the stomach. Microscopically, the cytoplasm of the tumor cells was abundant and eosinophilic. Immunohistochemical staining revealed that the tumor cells were positive for CD45RO and CD68. It is difficult to differentiate HS of stomach from other gastric malignancies by radiological evaluation alone. However, HS may be considered when a protruding and ulcerated mass in stomach shows heterogeneous hypervascular features. To the best of our knowledge, this is the first report in English language literature that emphasizes the imaging findings of human gastric HS.

[Extranodal Rosai-Dorfman disease of upper respiratory tract: a clinicopathologic study]

OBJECTIVE

To study the clinicopathologic features and differential diagnosis of extranodal Rosai-Dorfman disease (RDD) of the upper respiratory tract.

METHODS

The clinical, pathologic and immunohistochemical features of 10 cases of RDD were evaluated.

RESULTS

Among the 10 cases studied, there were 3 males and 7 females. The age of patients ranged from 20 to 61 years old (mean 38 years). The lesion arose in the nasal cavity (7 cases), nasopharynx (2 cases) or hard palate to trachea (1 case). Most of the patients presented with nasal obstruction, rhinorrhagia or tumor mass in the nasal/nasopharyngeal regions. CT scan often showed the presence of soft tissue lesion without bone destruction. Histologically, extranodal RDD was characterized by light-staining bands alternating with dark-staining bands. The light-staining bands were formed by aggregates of large round or polygonal histiocytes with emperipoiesis. The dark-staining bands were formed by abundant lymphoplasmacytic infiltrates. Immunohistochemical study showed that the histiocytes strongly expressed S-100 protein and partially expressed CD68. Six patients had no recurrence after surgical resection.

CONCLUSIONS

Extranodal RDD of the upper respiratory tract is a rare disorder of histiocytic proliferation, which usually involves the nasal cavity and paranasal sinuses. RDD can easily mimic rhinoscleroma, mainly due to the overlapping morphologic appearance. Immunohistochemical study is helpful in the differential diagnosis.

Quantitative PCR and immunohistochemical analyses of HMGB1 and RAGE expression in canine disseminated histiocytic sarcoma (malignant histiocytosis)

BACKGROUND

Disorders of histiocytic origin affecting humans and dogs share various similarities. Canine disseminated histiocytic sarcoma (DHS) (formerly known as malignant histiocytosis) is an aggressive neoplasm of interstitial dendritic cells (DCs). The receptor for glycation end products (RAGE) and the high mobility group box1 protein (HMGB1) have been shown to be required for the maturation and migration of DCs. Thus, deregulation of the expression of these genes could have a major effect on the progression of histiocytic disorders.

MATERIALS AND METHODS

Neoplastic canine DHS samples and non-neoplastic control samples were analysed immunohistochemically and via real-time PCR.

RESULTS

Significant down-regulation of RAGE in the lung tumour samples and down-regulation of HMGB1 in the lung, lymph node and spleen tumour samples were detected compared to their non-neoplastic counterparts.

CONCLUSION

RAGE and HMGB1 expression down-regulation in canine DHS points to a role in the progression of histiocytic disorders.

[Histiocytic sarcoma: a clinicopathologic study of 6 cases]

OBJECTIVE

To study the morphologic features, immunophenotypes, differential diagnoses and prognosis of histiocytic sarcoma (HS).

METHODS

The clinical and pathologic findings of 6 cases of HS were reviewed. Immunohistochemical assay (Elivision staining) was also performed. Follow-up information was available in 4 patients.

RESULTS

There were altogether 3 males and 3 females. The age of patients ranged from 12 to 81 years old (median = 54.6 years). The sites of involvement included lymph node (number = 2 cases) and skin or soft tissue (number = 4 cases). The tumor was composed of sheets of large epithelioid cells with abundant eosinophilic cytoplasm, oval to irregular nuclei, vesicular chromatin and large nucleoli. Binucleated form was not uncommon. Two of the cases showed increased pleomorphism with multinucleated tumor giant cell formation. Focal cytoplasmic with foamy appearance was identified in 3 cases. One case demonstrated foci of spindly sarcomatoid appearance. Hemophagocytosis was identified in 2 cases. Mitotic figures were readily identified. The tumor cells were often accompanied by various numbers of inflammatory cells. Immunohistochemical study showed that all cases were diffusely positive for leukocyte common antigen, CD4, CD68 and CD163. Four of the 5 cases studied also expressed lysozyme. Amongst the 4 patients with follow-up information available, 3 died of the disease at 6 to 11 months interval after diagnosis. One patient, whose lesion was localized at the skin and soft tissue, survived for 3 years, with no evidence of tumor recurrence.

CONCLUSIONS

Accurate diagnosis of the HS is based on the combination of morphologic examination and immunohistochemical assay. HS often presents with clinically advanced disease and pursues an aggressive clinical course, with a poor response to therapy. However, a subset of cases presenting with clinically localized lesion may carry a relatively favorable long-term outcome.

Is there a role for fibronectin upon true histiocytic lymphoma progression?

Cell interaction with extracellular matrix is a crucial event for various biological processes, including tumor progression. Although not exclusively, these interactions are frequently mediated by bidirectional signaling receptors known as integrins. Using a human histiocytic lymphoma-derived cell line (U-937), we evaluated the effects of ECM proteins and their integrin-type receptors in the regulation of cell attachment, proliferation, migration and survival. Fibronectin induces higher cell attachment in vitro when compared to laminin. Fibronectin also promotes a decrease in cell migration but do not modulate cell proliferation and death. Pre-incubation of U-937 cells with VLA-5 antagonistic peptides inhibited attachment of the cells to fibronectin-coated substrates. In a second vein, we observed that lymph node specimens obtained from diagnosed patient for true histiocytic lymphoma had greater deposition of fibronectin (but not laminin) around malignant clones. These results suggest that fibronectins play a relevant role in the establishment and progression of true histiocytic lymphoma cells.

Hematopoietic stem cell transplantation in Omenn syndrome: a single-center experience

We retrospectively analyzed the outcome of hematopoietic stem cell transplantations (HSCT) performed at our Center between 1991 and 2002 in 11 unselected patients with Omenn syndrome, a variant of severe combined immunodeficiency. The patients' mean age at the time of the first HSCT was 8.4 months. Two patients received two, and one patient three, HSCT procedures. The resulting 15 HSCT derived in seven cases from HLA-haploidentical parents, in four patients from matched unrelated donors, in three cases from an HLA phenotypically identical related donor, and in one case from an HLA genotypically identical family donor. Nine out of 11 patients are alive and immunoreconstituted 30-146 months after transplantation. At the time of the most recent evaluation, all of the nine survivors had normal T-cell function, and eight of them had developed normal antibody production. This study demonstrates an overall mortality of 18.2%, which is substantially lower than previously reported. Early recognition of OS, rapid initiation of adequate supportive treatment and HSCT lead to improved outcome for this otherwise fatal disease, regardless of the origin and matching of hematopoietic stem cells.

Histiocytic sarcoma with fatal duodenal ulcers

Histiocytic sarcoma is an uncommon neoplasm of mature histiocytes with very poor outcome. We report an autopsy case of a true histiocytic sarcoma with characteristic symptoms of so-called "malignant histiocytosis of the intestine". The liver and spleen were enlarged, with remarkable tumor cell infiltration in the hepatic sinusoids and splenic sinuses. Tumor cells aggregated to form sporadic nodular lesions in the liver, which often showed coagulative necrosis. Infarcted lesions also occurred at the splenic subcapsular area. In addition, tumor cell infiltration was noted in the sinuses of bone marrow and lymph node. Tumor cells often demonstrated moderate pleomorphism with multinucleated giant cells. They were positive for CD68 and negative for T- and B-cell lineage markers, megakaryocytic markers, and CD30. Various examinations were done to rule out infection-associated hemophagocytic syndrome, and the absence of infectious diseases was revealed. Thus, the diagnosis of histiocytic sarcoma was made. Apart from these lesions, multiple ulcerations, some with fatal perforation, were found in the esophagus and duodenum. They showed only non-specific inflammatory changes without tumor cell involvement. The ulcers probably derived from ischemic condition through an embolic process caused by tumor cell infiltration elsewhere in the blood vessels at the periphery of the ulcers.

Primary histiocytic sarcoma of the spleen associated with erythrophagocytic histiocytosis

We report an exceptional case of a histiocytic sarcoma presenting as a primary isolated spleen tumor in a 71-year-old woman. The neoplastic cells in the cords and sinuses of the red pulp formed multiple lobulated tumors, which were detected in vivo by ultrasound scan. The medium cells, large cells and the giant cells expressed CD68, a histiocyte-associated marker, lysozyme and S100 protein. All these cells were negative for B- and T-cell markers, cytokeratins, melanosome markers (HMB45) and CD1a (Langerhans' cells). Many tumor cells displayed strong erythrophagocytosis and sometimes lymphocytophagocytosis. In addition, numerous histiocytes with morphology indistinguishable from reactive macrophages also exhibited a strong erythrophagocytosis, and were found in the tumor as well as in the normal splenic parenchyma. Despite multi-agent chemotherapy, the patient suffered from a relapse in the liver, with a rapid fatal outcome. A literature review showed that such a primary splenic presentation with multiple tumors is rare. In contrast, in systemic malignant histiocytosis, secondary spleen involvement occurs more frequently but with diffuse infiltration. The association with a reactive histiocytosis with erythrophagocytosis corresponds to "histiocytic medullary reticulosis", as previously described by Scott and Robb-Smith.

Comparative fine-needle aspiration and pathologic study of malignant fibrous histiocytoma: Cytodiagnostic features of 95 tumors in 71 patients

To determine diagnostic cytomorphologic features of malignant fibrous histiocytoma (MFH) on fine-needle aspiration (FNA) materials, we reviewed the cytologic material and corresponding histologic slides of 95 tumors in 71 patients. Forty-four (46%) tumors were primary, 38 (40%) were recurrent, and 13 (14%) were metastatic. Histological variants of MFH were as follows: 52 (54.7%, 43 patients) were of the storiform/pleomorphic, seven (7.4%, five patients) were giant cells, four (4.2%, four patients) were inflammatory, and 31 (33.7%, 19 patients) were myxoid type. Review of original cytology reports showed that only 23 (24.2%) tumors were diagnosed as MFH and 68 (71.6%) as other types of malignancies. Four (4.2%) cases were reported as unsatisfactory/suspicious. Our findings showed that spindle-shaped, round, giant cells, osteoclastic-like giant, and inflammatory cells were the most consistent features that allow identification of the storiform/pleomorphic, giant cell, and inflammatory variants of MFH. The myxoid tumors had marked myxoid background matrix with spindle-shaped cells and, less frequently, round and giant cells. Pleomorphic leiomyosarcoma and dedifferentiated liposarcoma should be considered in the differential diagnosis of stroriphorm/pleomorphic, giant cells, and inflammatory variants of MFH. However, myxoid MFH may resemble their leiomyosarcoma and liposarcoma counterparts.

Malignant histiocytosis in childhood: A case report

A case of malignant histiocytosis (MH) in a 12-year-old male child is described. Fever and wasting were the most prominent symptoms. Bilateral cervical and axillary lymphadenopathy was present along with hepatosplenomegaly. The haematological, cytological and histopathological features are described. The diagnostic dilemma presented during the diagnosis of this case is also discussed. Diagn. Cytopathol. 1999;21:359-361.

Epstein-Barr virus (EBV)-induced CD30+ natural killer cell-type malignancy resembling malignant histiocytosis: malignant transformation in chronic active EBV infection associating hypogammaglobulinemia

A 27-year-old male suffered from Epstein-Barr virus (EBV)-related liver dysfunction with persistent hypogammaglobulinemia. IgG titers to EBV antigens were significantly high, while other hepatitis markers were negative. Liver biopsy disclosed active intralobular inflammation. Two years later, he manifested persistent fever, leukopenia, effusions and hypoproteinemia, and his general condition worsened progressively. The peripheral blood small lymphocytes predominantly expressed natural killer (NK)-like phenotypes (CD2+, CD7+, CD16+, CD56+). Hepatosplenomegaly and marked elevation of serum lactic dehydrogenase were observed. He died of respiratory failure at the age of 29. At autopsy, the liver (2190 g), spleen (860 g), small bowel and mesenteric lymph nodes showed massive infiltration of large atypical lymphoid cells in close association with hemophagocytic histiocytes. Involvement was mildly noted also in the bone marrow, lungs, gall-bladder and kidneys. The atypical cells belonged to CD30+ activated NK-type cells expressing CD2, cytoplasmic CD3 epsilon, CD7, CD45RO, CD56, HLA-DR and HLA-DQ. T cell receptors (TCR), surface CD3, CD4, CD5 and CD8 were not expressed. Epstein-Barr virus-related small nuclear RNA (EBER1) and Epstein-Barr virus-associated nuclear antigen 1 were detected in the nuclei of a significant number of atypical cells, while EBV-related latent membrane protein-1 was negative. EBER1 was also identified in the nuclei of non-neoplastic small lymphocytes at both biopsy and autopsy. Monoclonal integration of the EBV genome into the lymphoma cells was shown by Southern blot analysis. Clonal rearrangement of TCR was undetectable. Roles of chronic active EBV infection in the development of NK cell-type malignancy resembling malignant histiocytosis are discussed.

The effect of adriamycin against a liver metastatic model by encapsulation in liposomes

Antitumor activities of liposomes containing adriamycin (L-ADM) and their distribution process into tumour cells were analysed. The lipid composition of the liposomes was dimyristoylphosphatidylglycerol (DMPG)/egg phosphatidylcholine/cholesterol/adriamycin (ADM) in a molar ratio of 11.4:2:12:1.3. Liver-metastasizing murine tumour models, M5076 and L5178Y-ML, were used. In vivo antitumour effect against these tumour models was assessed from increase in life span (ILS). The survival prolongation effect of L-ADM in mice with liver failure caused by M5076 was significantly higher than that of F-ADM. In contrast, significant enhancement of the effects by encapsulation in liposomes was not observed in L5178Y-ML-bearing mice. In vitro cytostatic activities of L-ADM against M5076 cells as well as against other tumour cell lines were lower than those of F-ADM. The in vitro kinetic study on the distribution of L-ADM to the tumour cells revealed that ADM in L-ADM was taken up into the tumour cells mainly after it was released from the liposomes rather than taken up as the liposomal form. Among the cell lines tested, M5076 cells had the highest phagocytic activity and therefore the highest uptake activity of ADM during incubation with L-ADM. These findings suggest that the augmented antitumour activity of L-ADM in M5076-bearing mice was the result of phagocytosis of L-ADM by M5076 cells as well as the reduction of toxicity, prolonged retention of ADM in systemic circulation, and liver accumulation of ADM after administration of L-ADM.

Thyroid involvement by malignant histiocytosis of Langerhans' cell type

Involvement of the thyroid gland by Langerhans' cell histiocytosis is quite rare. We describe the case of a 58-year-old man referred for treatment of a progressively enlarging goitre. The trachea was severely stenotic and adjacent structures such as the left carotid vein and the thyroid cartilage were also involved. Central diabetes insipidus and severe combined immunodeficiency were associated. Although fine needle aspiration biopsy of the thyroid was initially interpreted as papillary carcinoma, anaplastic thyroid cancer was suspected. Treatment with prednisolone, doxorubicin and irradiation controlled the tracheal compression. A diagnosis of thyroid Langerhans' cell histiocytosis was finally made on the basis of the presence of Birbeck granules and CD1a and CD4 antigen in the thyroid tumour cells. Furthermore, positive staining for CD68 and lysozyme suggested that the tumour cells may have had the character of phagocytic cells in addition to their dendritic cell nature. This is the first case of thyroid involvement by malignant histiocytosis of Langerhans' cell type with unusual phagocytic markers.

[Immunohistochemical localization and serum testing for ferritin in malignant histiocytosis]

Localization of ferritin with immunohistochemical staining was carried out in thirty six cases of malignant histiocytosis (MH). The positivity rate for ferritin was 100 per cent. Ferritin was found to exist in the cytoplasm of the tumor cells. Image analysis showed that ferritin level in the well-differentiated histiocytes (1.2314) was higher than that in the atypical histiocytes (0.7181) (P < 0.01). Ten MH patients showed surprising high serum ferritin concentration (1482.3 ng/ml) than that in normal. Our data suggest that ferritin is the tumor associated antigen in MH. The synthesis and release of ferritin by MH tumor cells is the important cause for the high concentration of serum ferritin in patients.

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.

Lymphomas of true histiocytic origin. Expression of different phenotypes in so-called true histiocytic lymphoma and malignant histiocytosis

The authors determined the phenotypes of neoplastic cells in true histiocytic lymphoma and malignant histiocytosis by using a large panel of monoclonal antibodies and enzyme histochemistry procedures. Although the phenotypes overlapped slightly, the authors noted a distinct pattern in these tumors. The tumor cells of malignant histiocytosis generally expressed the monocyte markers CD11b, CD11c, CD14, and CD45, especially after induction with phorbol ester. In contrast, the tumor cells of true histiocytic lymphoma exhibited a marker expression very similar to that of Reed-Sternberg cells in Hodgkin's disease. These cells expressed markers CD30, 2H9, and 1A2, but rarely expressed CD11b, CD11c, CD14, or CD45. Regardless of their cytologic features, the tumor cells from both types of histiocytic lymphoma exhibited diffuse nonspecific esterase and acid phosphatase activities, and they expressed histiocyte markers CD15, CD68, LN5, 1E9, and M387 to varying degrees. The tumor cells from both lymphomas did not exhibit T- or B-cell markers, T-cell receptor or immunoglobulin gene rearrangements, or gene translation products, even when they were induced with phorbol ester. The phenotypic expression in these two histiocytic malignancies suggests that they are derived from different types of histiocytes, or from histiocytes in different stages of maturation or differentiation, or from histiocytes that have distinct mechanisms of tumorigenic transformation. The expression of circulating monocyte markers in malignant histiocytosis suggests that this tumor originates in monocytes or free histiocytes, whereas the phenotype of true histiocytic lymphoma is compatible with an origin in fixed histiocytes, which generally are devoid of the monocyte markers CD11b and CD14.

[Mechanism of hyperferritinemia in a case of malignant histiocytosis]

We report a case of malignant histiocytosis diagnosed by liver-spleen biopsy under laparoscopy. A 49-year-old woman was admitted to our hospital with thrombocytopenia, moderate anemia and hypoproteinemia. Her bone marrow findings revealed erythroid and megakaryocyte hyperplasia, and the serum ferritin concentration was 2,250 ng/ml though she had not received any blood transfusions. Ferrokinetics analysis showed the pattern of ineffective erythropoiesis, and the half-lives of erythrocytes and platelets were both shortened. Her hepatosplenomegaly gradually increased accompanied by increasing serum ferritin level to 10,000 ng/ml. Liver-spleen biopsy was carried out under laparoscopy and revealed infiltration of atypical histiocytes with erythrophagocytosis, which were positive for S-100 and ferritin but negative for lysozyme. The rate of glycosylation in whole serum ferritin, analyzed by using concanavalin-A binding method, showed that her glycosylated ferritin content was only 8.3%, whereas in sera after iron overloading, it was about 70%. Serum isoferritin profiles by isoelectric focussing were studied, and isoferritin pattern from malignant histiocytosis was the same as that in iron overloading after neuraminidase treatment. These findings suggest that serum ferritin is synthesized in proliferating histiocytes and released in the plasma as a nonsecretory type (nonglycosylated ferritin) in this case.

An immunocytochemical study on the distribution of ferritin and other markers in 36 cases of malignant histiocytosis

The distribution of ferritin in 36 autopsy cases of malignant histiocytosis was investigated by immunocytochemical staining, together with the detection of alpha 1-antichymotrypsin, alpha 1-antitrypsin, lysozyme, S-100 protein, and ricinus communis agglutinin in the consecutive sections. The results showed that ferritin-positive tumor cells were present in every case. The quantity of cellular ferritin in well-differentiated histiocytes was higher than that in atypical histiocytes. Double labeling showed that ferritin and alpha 1-antichymotrypsin might be located either in one tumor cell or in separate cells. Our data suggest that ferritin may be a tumor associated antigen in malignant histiocytosis, playing a regulatory role for tumor cell differentiation.

An autopsy case of so-called midline malignant reticulosis followed by extensive dissemination with immunohistochemical evidence for its T cell malignancy

An autopsy case of malignant midline reticulosis (MMR) is reported. The patient, a 42-year-old Japanese male, died after a clinical course of 22 months. Autopsy revealed extensive infiltration of generalized organs by the tumor cells, suggesting that the disease was highly malignant in nature. Staining with monoclonal antibodies against T-cell surface antigens Leu 4 on frozen sections and UCHL1 on paraffin-embedded sections enabled us to examine the phenotype of the tumor cells with good morphological preservation and to verify the T cell nature of the tumor.

Peripheral T-cell lymphoma presenting as hemophagocytic syndrome

Three patients with peripheral T-cell lymphoma presenting with pyrexia, wasting, hepatosplenomegaly and pancytopenia in the absence of myelophthisic lymphomatous involvement are reported. Early in the course of the disease when there was no significant lymphadenopathy, these cases created enormous diagnostic confusion. Although the clinical features were suggestive of malignant histiocytosis (MH), marrow findings showed phagocytic histiocytes which did not appear atypical, and the criteria for diagnosis of MH could not be satisfied. Lymph node enlargement was detected only after 14, 5, and 8 weeks from the onset of symptoms, and the diagnosis of T-lymphoma was then made on lymph node biopsies. Treatment with multiple agent chemotherapy was attempted. Two patients died 3 days and 11 weeks after treatment was started and the third was lost to follow-up. In contrast with most of the cases reported in the literature, our cases show that a reactive hemophagocytic syndrome can be an early and prominent manifestation of an underlying T-cell lymphoma. Differentiation from other causes of hemophagocytic syndrome can be difficult and lack of histological proof of malignancy in the initial stage often delays definitive diagnosis and treatment.

[An autopsy case of malignant histiocytosis-like disorder following hypersensitive reaction to mosquito bite]

An autopsy case of an 18-year-old Japanese girl with a malignant histiocytosis-like disorder that developed during the course of a hypersensitive reaction to mosquito bite is reported. Episodes of hypersensitive reactions to mosquito bite had been repeated since she was 12 years old and at the age of 18 years she died of acute respiratory failure only 11 days after a mosquito bite. On autopsy, the dermal reaction to the last mosquito bite had already calmed down, and 'poorly differentiated histiocytes', which were presumed from their histochemical characteristics, had remarkably infiltrated into multiple organs, appearing like leukemic infiltration. Only a small number of them were noted in the lymph nodes and the bone marrow. The results of histochemical examination of 'poorly differentiated histiocytes' was as follows: (1) Neither markers for granulocytes (peroxidase and naphthyl AS-D Cl esterase) nor markers for lymphocytes and plasma cells (leukocyte common antigen and immunoglobulins) were detected. (2) Some markers for histiocytes (peanut lectin agglutinin and lysozyme) were positive in some of the proliferated cells. (3) A marker for T-zone histiocyte (s-100 protein) was negative. These results suggested that the proliferated cells included cells of the monocyte-macrophage system. These cells morphologically showed no phagocytic activity and were suggested to be immature histiocytes. Jurco et al. reported (poorly differentiated) malignant histiocytosis consisting of immature histiocytes without phagocytic activity, by using histochemical methods.(ABSTRACT TRUNCATED AT 250 WORDS)

[Ultrastructural and cytochemical studies of malignant histiocytosis]

The internal and surface ultrastructure and cytochemistry (MPO, AP) of the histiocytes from 16 patients were studied. The results showed that poorly differentiated histiocyte was irregular in cell contour with various projections. All had more or less neoplastic histiocytes in which numerous vacuoles and blisters along peripheral plasma membrane were seen. The neoplastic cells had numerous lysosomes, abundant short strands of rough endoplasmic reticulum, and free and poly-ribosomes in the cytoplasma. Long profiles and ring of RER as well as expansive forms were seen in 4 cases. The mitochondria were generally normal although an occasional elongated form and their cristae showed destroyed architecture in 6 cases. Occasionally, perinuclear bundles of microfilaments and prominent Golgi apparatus were seen. The nuclei of the neoplastic histiocytes were irregularly shaped and most had one or two huge nucleoli. Circular nuclear bodies were often seen. The ultrastructural cytochemistry of the neoplastic histiocytes showed: MPO was weakly positive in about 1/4 to 1/2 of the cells. AP reaction in all of the neoplastic histiocytes was always strongly positive located in the nuclear membrane. RER, lysosomes granules and Golgi apparatus. Under SEM, various surface characteristics of the neoplastic histiocytes were seen such as bleb-covered surface; bleb-ruffled surface, and ruffled surface.

An autopsy case of malignant histiocytosis with Reed-Sternberg-like cells

We report an autopsy case of malignant histiocytosis. The clinical course was rapidly progressive and terminated with jaundice and respiratory failure. Histologically, there was diffuse infiltration of large atypical cells in the liver, spleen, lymph nodes and bone marrow. It was of interest that these tumor cells contained a number of bizarre multinucleated cells histologically indistinguishable from Reed-Sternberg cells of Hodgkin's disease, and that these atypical cells expressed DAKO M1 (identical to Leu M1) and Ki-1 antigens and also showed binding to peanut agglutinin (PNA), representative markers of Reed-Sternberg cell. An absence of epithelial membrane antigen and presence of Leu M1 antigen in the tumor cells made a diagnosis of Ki-1 lymphoma unlikely. This case study showed that giant or pleomorphic cells indistinguishable histologically and phenotypically from Reed-Sternberg cells occur in malignant histiocytosis.

Malignant histiocytosis in childhood: clinical, cytochemical, and immunohistochemical studies of seven cases

Tissue specimens obtained at autopsy from seven childhood cases of malignant histiocytosis were studied by immunohistochemistry. Clinically, the majority of the cases showed sustained fever, hepatosplenomegaly, pancytopenia, and DIC. The pretreatment diagnosis was based on their typical clinical manifestations and bone marrow smear findings. Although three patients temporarily responded to exchange transfusion and chemotherapy, all seven patients eventually died of active disease. Postmortem examination revealed the proliferation of atypical histiocytes appearing in variable degrees of maturation in the lymph nodes, liver, spleen, bone marrow, lungs, and central nervous system. Immunohistochemical staining for lysozyme, nonspecific cross-reacting antigen (NCA), alpha 1-antitrypsin (alpha 1 AT), alpha and beta subunits of S100 protein (S100 alpha, beta), and concanavalin A receptors (ConAR) in cytoplasm demonstrated the presence of two subtypes of malignant histiocytes, ie, S100 beta+/NCA-/ConAR+ (4 cases) and S100 beta-/NCA+/ConA R+ (three cases). The results of lysozyme, alpha 1 AT, and S100 alpha staining were inconsistent. A survey of the literature disclosed that the incidence of S100 protein-positive cases in children was higher than in adults (12/21 v 5/19; chi 2, P less than .05). Further large scale investigation is necessary to confirm the independence and significance of these two subtypes of histiocytes in malignant histiocytosis.