Clusters Of Epithelioid Cells Research Articles

Immunohistochemical Expression of Tenascin in Normal Human Salivary Glands and in Pleomorphic Adenomas

The presence of the extracellular matrix glycoprotein tenascin was studied immunohistochemically in normal human salivary glands and in pleomorphic adenomas. Its expression was compared to that of fibronectin, and type IV collagen. In the normal salivary gland, tenascin was found with interruptions in periductal tissues, and continuously in blood vessels, fat cells and around nerve bundles. In pleomorphic adenoma, tenascin was detected surrounding the clusters of epithelioid cells, in areas with a myxoid and a chondroid matrix, and around some myoepithelial cells as a halo. As compared to fibronectin, there is a similar location of tenascin and fibronectin around tumor cell clusters but not in myxoid and chondroid matrices. Fibronectin was found around the cells in chondroid matrix. In conclusion, tenascin is not only found in malignant tumors but also in benign tumors such as pleomorphic adenoma. The presence of tenascin as a halo around myoepithelial cells suggests a role of these cells in development of myxoid and chondroid matrices.

Monocytoid B Lymphocytes and Epithelioid Cell Clusters in Abscess‐forming Granulomatous Lymphadenitis With Special Reference to Cat Scratch Disease

In order to clarify the appearance of monocytoid B lymphocytes (MBLs) in abscess-forming granulomatous lymphadenitis (AGL) and the relation between AGL and cat-scratch disease (CSD), 48 cases of AGL were studied histologically. MBLs were present in about 50% of AGL cases. Warthin-Starry (WS) silver stain-positive bacteria, which are the causative agent of CSD, were present in 52.4% of AGL cases with MBLs and 59.2% of AGL cases without MBLs. The appearance of MBLs in AGL was not related to various clinical features, including disease interval from initial lymphadenopathy to lymph node biopsy. Histologically, epithelioid cell clusters appeared in about 70% of MBL-positive AGL cases, but were not observed in MBL-negative AGL. Therefore, a close interaction between MBLs and epithelioid cells in AGL is suggested, and we emphasize that the histological features of some AGL cases resemble those of toxoplasmic lymphadenitis.

Ｔ細胞性リンパ腫におけるサイトカイン遺伝子発現

Recent studies have suggested that some cytokines are involved in the growth of lymphoid neoplasma. We studied the production of cytokines in 28 patients with T-cell lymphoma using the northern blotting analysis and the immunohistochemical technique.Of 28 cases of T-cell lymphoma, IL-4 was detected in 9 cases and IFN-γ was detected in 8 cases. IL-3, TNFα and GM-CSF were detected in 1, 1 and 2 cases, respectively. With regard to histologic subtype of 8 cases which expressed IL-4, 2 cases were angioimmunoblastic lymphadenopathy type and 3 cases were angiocentric lymphoma in sinonasal region, which showed the characteristic histology.All 8 cases expressing IL-4 showed increased immunoglobulin in sera. Since IL-4 has a variety of biological activities for not only B-cells but also T-cells, these results indicate that IL-4 may play an important role in the histopathogenesis and the growth of T-cell lymphoma.In the cases which expressed IFN-γ, T-zone histocytes and/or the clusters of epithelioid cells were seen more frequently. It suggests that IFNγ may be involved in the formation of Lennert's lesion.

Cutaneous Lymphoepithelioid Lymphoma (Lennertʼs Lymphoma)

Lymphoepithelioid lymphoma (LEL) is a peculiar type of low grade malignant T cell lymphoma usually arising in lymph nodes, characterized immunohistologically by predominant T-helper/inducer lymphocytes intermingled with clusters of epithelioid cells. An uncommon case of LEL with cutaneous involvement is reported with additional reference to ultrastructure and DNA-flow-cytometric analysis (DNA-FCM) of the lymphoma. Light microscopy showed subepidermal bandlike infiltrates of lymphocytes and clusters of epithelioid cells extending into the subcutaneous tissue. By immunohistochemistry the presence of a high percentage of T-helper/inducer lymphocytes was confirmed. DNA-FCM demonstrated an aneuploid cell population indicating malignant cells. Our results are in accordance with earlier ones established in lymph nodes.

Wall structure of arteriovenous anastomoses in the rabbit ear. Combined light-, scanning- and transmission electron-microscopic studies.

The wall structure of arteriovenous anastomoses in the rabbit ear was investigated. (1) Clusters of epithelioid smooth muscle cells form 3-4 longitudinally oriented plicae. The channel shows a single, irregularly outlined lumen, and its wall is very thin between adjacent plicae. (2) Endothelial cells covering the plicae protrude into the lumen, thus suggesting active contraction or shortening of the plicae. (3) The tunica adventitia is composed of 4-6 sheaths of flat fibroblasts, which may serve as a barrier to prevent loss of neurotransmitters. Processes of some of the fibroblasts also extend into the tunica media. (4) The tunica media is composed of an outer circular layer of typical smooth muscle cells, and an inner longitudinally running plica of ramified smooth muscle cells. Wide intercellular spaces between these ramified cells are filled with collagen fibrils, microfibrils, amorphous intercellular substances, and fibroblasts. Fibroblasts form close membrane contacts with each other, and with the smooth muscle cells. (5) Fibroblasts and other connective tissue components may function as an elastic support during active motility of the anastomotic channel.

Immune response of mice to ingested Toxoplasma gondii: a model of toxoplasma infection acquired by ingestion.

SWR/J mice perorally infected with the Me49 strain of Toxoplasma gondii developed thymic cortical atrophy, clusters of epithelioid cells and plasma cells in lymphoid tissue, and hepatic inflammation during the first month after infection; the inflammation subsequently decreased. Antibody to T gondii was present in serum on day 14 after infection, reached a maximal titer by one month, and remained at this titer for five months. Splenic lymphocyte blastogenesis in response to concanavalin A was depressed for one month but returned to normal in most mice by two months. Splenic lymphocyte blastogenesis in response to toxoplasma antigens (stimulation index, greater than or equal to 1.6) developed in one-third of mice after two months of infection but did not develop in others even after five months of infection. Peritoneal macrophages had an enhanced microbicidal capacity against T gondii from 14 days until five months after infection. Peroral administration of the Me49 strain of T gondii was lethal for Beige-C57BL/6J and C57BL/6J mice; these strains of mice showed the most extensive changes, necrosis, thrombi, and many trophozoites in tissues.

Malignant lymphoma simulating lymph node toxoplasmosis.

On histological examination of 667 cases originally suspected of lymph node toxoplasmosis, 12 cases were diagnosed as malignant lymphoma and 15 cases as atypical hyperplasia (AH), suspicious of malignant lymphoma. All 12 malignant cases were of Hodgkin's disease: eight of the lymphocyte predominant nodular type, two of lymphocyte predominant diffuse type, and two of the nodular sclerosis type. In all cases, the lymph nodes contained small groups of epithelioid cells which were virtually indistinguishable from those seen in toxoplasmosis. In the differential diagnosis between lymph node toxoplasmosis and malignant lymphoma, the following features were found helpful. In toxoplasmosis the general structure is preserved and germinal centres are frequent, while in malignant lymphoma and in AH the general structure is destroyed. However, in some cases of toxoplasmosis germinal centres may be difficult to identify because their margins are indistinct due to clusters of epithelioid cells. Also, in some types of Hodgkin's disease and in some cases of AH with epithelioid cells, the general structure of the lymph node may be partially preserved. The occurrence of epithelioid cells within germinal centres seems to be a specific feature for toxoplasmosis; it was never seen in malignant lymphoma nor in AH. The occurrence of strands of monocytoid cells (unreife Sinushistiocytose) though a fairly typical feature of toxoplasmosis, was also occasionally seen in Hodgkin's disease or AH.

Malignant lymphoma with a high content of epithelioid histiocytes.A distinct clinicopathologic entity and a form of so-called „Lennert's Lymphoma”

Detailed pathologic and clinical findings in 19 patients with malignant lymphoma with a high content of epithelioid histiocytes (MLEH) are presented. The essential morphologic features for inclusion in this study comprised a diffuse architectural pattern; obliteration of normal nodal architecture; small, poorly defined clusters of epithelioid cells scattered throughout the stroma; and proliferation of atypical small and large lymphoid cells in varying proportions. Males predominated and the patients' ages ranged from 23 to 75 years, with a median age of 49 years. All patients had cervical adenopathy. Generalized adenopathy and splenomegaly occurred in approximately half. Hepatomegaly was less frequent, but the liver was histologically involved in four of seven patients in whom biopsies were performed. Skin rashes developed in two, but Waldeyer's ring involvement was noted in only one patient. More than half of these patients had „B” symptoms. Staging procedures disclosed that 74% were pathologic Stage IV. In seven surgically staged patients, the histologic features in the initial diagnostic lymph node biopsy were reproduced in the involved tissues at laparotomy. All patients received a variety of single agent and/or combination chemotherapy. Four patients received radiotherapy in addition to chemotherapy. The median survival was 15.6 months. Thirteen patients have died, all with clinical evidence of residual lymphoma. The cause of death in six was infection. In two of the four autopsies, the epithelioid cell component was absent and the microscopic features were indistinguishable from diffuse lymphoma of mixed cell type. While this disorder shares certain clinical and histologic features with Hodgkin's disease and with angioimmunoblastic lymphadenopathy, our observations lead us to the conclusion that MLEH, as defined in this paper, should be considered a variant of a non-Hodgkin's lymphoma and a distinct clinicopathologic entity.

Über das Vorkommen von epitheloiden Glomusstrukturen in den untersuchten Lymphknoten operierter Mamma-Karzinome

A report is presented on the demonstration of epithelioid cell clusters within the axillary lymph node group, which - in the absence of knowledge of their structural peculiarities - could be taken for micrometastases of a solid mammary carcinoma. The lymph node material from 400 extensively excised mammary carcinomas with obligatory lymphonodectomy was available for this study. Microscopic inspection of successive sections at intervals of 100 μ was performed following fixation and optical demonstration of all lymph nodes in a picric acid medium. This procedure led to the discovery of epithelioid cell clusters in 18 out of the 400 cases examined. As regards their appearance, with direct allocation to the local vascular stroma, these clusters must be regarded as glomus-like structures. In no case could metastases of a mammary carcinoma and the epithelioid cell foci mentioned here be demonstrated either next to each other or combined. In appearance they are remarkably similar to the already known glomus structures of other sites. The presence of such structure in lymph nodes is most likely attributable to micromorphous malformation of vessels in the sense of hamartia. From a clinical point of view, their fundamental significance consists in the necessary differentialdiagnostic demarcation against metastase of solid carcinoma in the region of origin of the lymph.

Cell culture of the endocrine pancreas of the mouse in chemically defined media

Monolayer cultures of endocrine pancreatic cells from both fetal and postnatal mice have been established on a chemically defined medium, MPNL65/C, of high osmolality (340 mOsm). Precocious settling and attachment of fibroblastoid cells over the first 12 hr in vitro permitted the establishment, by decanting, of clusters of epithelioid cells in culture with very little fibroblastic contamination. Substituting high osmolality medium MPNL65/C at 36 hr of culture resulted in cytotoxic changes in contaminating fibroblasts within a few days; on the contrary, rapid cell outgrowth from the epithelioid clusters to form monolayers was not retarded. As determined by light microscopic observation of living and stained cultures, the pancreatic β cell was the major surviving cell species; no differentiated exocrine cells were detected; the question of other surviving endocrine cell types (α-1, α-2 cells) was not resolved. That the cultured β cells were endocrinologically competent was demonstrated by their synthesis and secretion of insulin. However, the levels of insulin secretion declined with increasing time in culture, and disruption of the monlayer due to unexplained causes was seen between the 3rd and 4th weeks in vitro. The murine monlayer cultures were unresponsive to glucose stimulation of insulin secretion, and in this way differed from primary pancreatic cell cultures of other mammalian species described by others.

Monolayer cell culture of neonatal rat pancreas: An ultrastructural and biochemical study of functioning endocrine cells

Cells obtained by enzymatic dissociation of newborn rat pancreases grown in monolayer culture for periods of 14 hours to 20 days were utilized for ultrastructural and physiological studies. Small clusters of epithelioid cells, first recognized at 14 hours, increased in size with time, frequently merging to form large sheets of cells surrounded by fibroblastoid cells. Endocrine B and A cells were the most numerous elements in the clusters. The integrity of their differentiated ultrastructure was documented by the accumulation of stored immunoreactive insulin and immunoreactive glucagon within the cultures and the ability to regulate their release into the medium by means of normal physiological stimuli. The morphophysiological integrity of the B cells was also demonstrated in a pulse-chase experiment by closely correlating the movement of 3 H-leucine into proinsulin and insulin with sequential labeling by autoradiography of the rough endoplasmic reticulum, Golgi, and secretory granules. Furthermore, the presence of mitotic division among granulated cells provided evidence of B-cell replication. In contrast, surviving pancreatic exocrine cells underwent progressive morphologic simplification, giving rise to a population of dedifferentiated epithelioid cells whose ultimate fate requires further study.

Monolayer cell culture of neonatal rat pancreas: light microscopy and evidence for immunoreactive insulin synthesis and release.

Pancreatic cells from neonatal rats, isolated by repeated exposure to a mixture of trypsin and collagenase, were cultured in monolayer for periods up to 19.5 days. This preparation was characterized by: (1) light microscopy combined with morphometric analysis; and (2) measurements of immunoreactive insulin (IRI) and protein content of cultured cells and of the amounts of IRI released into the culture medium. The major problem encountered was the rapid proliferation of fibroblastoid cells which tended to overgrow the culture. The decantation of the primary cell suspension after 14 hrs of culture produced a preparation enriched in epithelioid cells, which appeared as clusters. Contained in these clusters were aldehyde-thionin positive cells, presumably B cells. The number of clusters of epithelioid cells did not change over an 8.5 day culture period, but the size of the individual clusters diminished with time. The protein content of cultured cells, which probably reflects the degree of contamination by fib...