Cutaneous malignant epithelioid neoplasms.

In summary, cutaneous malignancies with an epithelioid appearance form a diverse group of neoplasms that may be difficult to diagnose by utilizing routine microscopy alone. Cutaneous malignancies, including malignant melanoma and metastatic carcinoma, certain benign neoplasms such as mixed tumor of the skin and angiolymphoid hyperplasia with eosinophils (epithelioid hemangioma), and infectious conditions such as bacillary (epithelioid) angiomatosis can be considered in this differential. However, through recognition of the characteristic histologic, immunocytochemical, and ultrastructural findings outlined above, definitive diagnosis of these challenging neoplasms is usually possible.

Wistar Furth rat megakaryocytes lack dense compartments and intercellular plaques, membranous structures rich in cytoskeletal proteins.

Wistar Furth (WF) rats have an abnormal thrombopoietic phenotype with morphologically aberrant megakaryocytes, larger than normal mean platelet volume, and platelet alpha-granule protein deficiency. Here, ultrastructural comparisons of WF rat megakaryocytes to those of rats (Wistar) with normal platelet formation during stimulated megakaryocytopoiesis following 5-fluorouracil administration, have revealed a previously unrecognized membrane structure in normal rat megakaryocytes, and two additional abnormalities in WF megakaryocytes. The novel structures were zones of electron density on the cytoplasmic face of apposed plasma membranes of adjoining normal megakaryocytes. These modified focal adhesion-type contacts were distributed at intervals between adjacent megakaryocytes, and were spaced by deposits of extracellular material. These structures also were present between apposed plasma membranes of Wistar rat megakaryocytes in unperturbed marrows, but were absent between megakaryocytes of WF rats. The second WF rat megakaryocyte abnormality is the absence of cytoplasmic dense compartments, another specialized membranous structure that is continuous with the megakaryocyte demarcation membrane system. Both the intercellular plaques and dense compartments of Wistar rat megakaryocytes were found to be rich in cytoskeletal proteins including actin, alpha-actinin, talin, and vinculin as indicated by ultrastructural immunogold labeling. We hypothesize that an abnormality in cytoskeletal protein function may be responsible for the lack of these structures in the WF rat.

Nodular sclerosing Hodgkin disease with primary manifestation in the orbit.

Hodgkin disease with primary manifestation in the orbit is extremely rare, and even when suspected can be very difficult to diagnose. Its clinical and histological presentation can be nearly impossible to differentiate from that of a benign inflammatory process, and it is necessary to utilize immunohistochemical techniques to confirm the diagnosis. This article focuses on a case of nodular sclerosing Hodgkin disease with initial manifestation in the orbit. A comparison of the clinical, histological, and immunohistochemical presentations associated with both Hodgkin disease and benign inflammation is discussed. A brief review of the immunohistochemistry specific for Hodgkin disease is also provided.

Origin and rapid evolution of a novel murine erythroleukemia virus of the spleen focus-forming virus family.

The Friend spleen focus-forming virus (SFFV) env gene encodes a glycoprotein with apparent Mr of 55,000 that binds to erythropoietin receptors (EpoR) to stimulate erythroblastosis. A retroviral vector that does not encode any Env glycoprotein was packaged into retroviral particles and was coinjected into mice in the presence of a nonpathogenic helper virus. Although most mice remained healthy, one mouse developed splenomegaly and polycythemia at 67 days; the virus from this mouse reproducibly caused the same symptoms in secondary recipients by 2 to 3 weeks postinfection. This disease, which was characterized by extramedullary erythropoietin-independent erythropoiesis in the spleens and livers, was also reproduced in long-term bone marrow cultures. Viruses from the diseased primary mouse and from secondary recipients converted an erythropoietin-dependent cell line (BaF3/EpoR) into factor-independent derivatives but had no effect on the interleukin-3-dependent parental BaF3 cells. Most of these factor-independent cell clones contained a major Env-related glycoprotein with an Mr of 60,000. During further in vivo passaging, a virus that encodes an Mr-55,000 glycoprotein became predominant. Sequence analysis indicated that the ultimate virus is a new SFFV that encodes a glycoprotein of 410 amino acids with the hallmark features of classical gp55s. Our results suggest that SFFV-related viruses can form in mice by recombination of retroviruses with genomic and helper virus sequences and that these novel viruses then evolve to become increasingly pathogenic.

Localization of megakaryocytes in normal mice and following administration of platelet antiserum, 5-fluorouracil, or radiostrontium: evidence for the site of platelet production.

The relative contributions of various organs to platelet production is controversial. In this study, serial histologic sections of bone marrow, spleen, liver, and lung from normal C57BL/6J mice and mice that had received three different agents which perturb normal murine thrombopoiesis (platelet antiserum, 5-fluorouracil, and radioactive strontium) were examined for the presence of megakaryocytes, utilizing morphologic and immunohistochemical techniques for their identification. In liver and lung tissue, megakaryocytes (including their naked nuclei or large cytoplasmic fragments) were rare in whole cross-sections (which included blood vessels) from normal and perturbed mice, even during periods of strong stimulation of thrombopoiesis. In contrast, megakaryocyte numbers were greatly increased in bone marrow and/or spleen tissue in these circumstances. We conclude that: 1) the bone marrow and spleen are the major thrombopoietic organs in the mouse, and 2) an insignificant fraction of thrombocytopoiesis occurs in the murine liver or lung, even during periods of greatly increased platelet production or following loss of the spleen and/or bone marrow.

IL-3 and ribavirin induce differentiation and growth suppression during long-term treatment of a megakaryocytic leukemia cell line.

Differentiation of the megakaryocytic leukemia cells, CMK, was induced by long-term (12 day) treatment with the combination of IL-3 and the nucleoside analogue ribavirin (RV), which reduces cellular GTP levels. In a previous report we demonstrated the induction of early messages and antigens, as well as the formation of giant polyploid cells in the cultures (Majumdar et al., 1994, J. Cell. Physiol., 160:29-39). Here we show high level induction of messages for the late markers, Platelet Factor 4, GMP140 (P-Selectin), thrombospondin, and beta thromboglobulin. The induced cells are also positive for these antigens by immunocytochemical analysis. The high level message induction resulted from synergy between the inducers. Pretreatment of the cells with IL-3 could accelerate the rise in message seen with the inducer combination. The increase in differentiation markers was accompanied by a reduction of the proliferative capacity of the cells. Riboguanosine, which has anti differentiation activity, blocked the induction of early and late antigens by the inducer combination, and also by IL-3 acting alone, but did not block the reduction in proliferative competence. In this model of megakaryocytic differentiation IL-3 treatment yields an initial stimulation of growth followed by growth suppression, and is the principal driver of the differentiation process. RV functions primarily as a stimulator of message and protein expression in synergy with IL-3.

Immunohistochemical approaches to diagnosis in gynecologic pathology.

Immunohistochemical techniques have become widely used in gynecologic pathology in recent years. This article is divided into sections of major anatomic areas of gynecologic interest, and each section discusses specific pathologic questions approachable by these studies. A description of reagents, as they apply in each case, is also included.

Juvenile xanthogranuloma: a clinical, histopathologic and immunohistochemical study.

Juvenile xanthogranuloma (JXG) is a benign histiocytic proliferation of uncertain histogenesis which usually resolves spontaneously. Histopathologically, classic lesions are characterized by diffuse proliferations of foamy histiocytes, many of which may be multinucleated (Touton cells), admixed with lymphocytes and eosinophils. Histologic variants of JXG, perhaps representing evolving lesions, may lack these typical histopathological features, showing diffuse infiltrates of non-foamy mononuclear histiocytes without Touton cells, posing problems in differentiation from other histiocytic or melanocytic proliferations. Immunohistochemically, JXG is characterized by variable expressions of several histiocytic markers as well as the absence of staining for S100 protein. To assess better the spectrum of histopathological and immunohistochemical features of JXG, we studied nine cases of classic or histologic variant of JXG. The cases were evaluated by light microscopy and with an extensive battery of antibodies. All 9 cases, regardless of their light microscopic appearance, showed markedly positive staining with histiocytic markers including CD68, HAM56, cathepsin B and vimentin, but did not stain for S100 protein. Antibodies to factor XIIIa stained positively in 8 cases while staining for other markers was variable. Our results suggest that the histiocytes in JXG lesions have macrophagic differentiation, probably representing a reactive process to an unknown stimulus.

A simple technique for preservation of fixation-sensitive antigens in paraffin-embedded tissues.

Immunohistochemistry is a powerful tool for tissue diagnosis and research. Although the frozen section has remained the gold standard for this important approach to evaluation of antigens in tissues, there is widespread acknowledgment of many limitations. Routine paraffin-embedded sections ware widely used for morphological examination of tissues but are not optimal for antigen preservation. In this study, paraffin-embedded tissues fixed with a simple buffer containing zinc as the primary fixative were compared with tissues fixed with routine formalin, zinc-formalin, paraformaldehyde, ethanol, a variety of commercial (non-formalin-containing) fixatives that have been recommended for reduced toxicity and improved antigen survival, and frozen sections. Human lymphoid tissues and a group of antibodies to antigens (CD1, CD4, CD7, CD8, CD19) usually preserved only in frozen tissue were used as a model system. Fixation in a simple solution of zinc acetate and zinc chloride in a Tris-Ca acetate buffer resulted in antigen preservation comparable to that in frozen sections with antibodies to these cell surface markers. Morphological preservation was comparable to formalin-fixed sections. The work presents a new method that represents the closest approach yet to a technique that combines optimal antigenic survival with the convenience and morphological preservation of traditional formalin-fixed tissue embedded in paraffin.

IL-3 and ribavirin induce high level expression of megakaryocytic markers and messages during long-term treatment of a megakaryocytic leukemia cell line.

Megakaryocyte differentiation is a lengthy process with cells moving through a continuum delineated by the sequential expression of specific gene products. The limited number of primary cells available from marrow for analysis has brought attention to some leukemic cell lines which show enhanced megakaryocyte marker expression following incubation with inducing agents, the most common of which is phorbol myristate acetate (PMA). We developed an alternative induction protocol for the megakaryocytic leukemic cell line CMK, which involved incubation of the cells with IL-3 and the nucleoside analog, ribavirin, for 1-2 weeks. This treatment was neither toxic nor cytostatic and yielded increased levels of the surface glycoproteins GPIIb/IIIA and GPIb-IX. Levels of some megakaryocytic messages (GPIIIa, GPIX) showed a marked rise by 12 days of incubation in the inducer combination. This was due to a synergistic interaction between IL-3 and ribavirin which influenced both transcriptional and posttranscriptional events. Light and electron microscopy demonstrated the presence of large polyploid cells, with morphological features similar to those of megakaryocytes, in the induced cultures. Analysis of the heterogeneity of response in the cell population to the induction regimen after several days of treatment suggested that cells which failed to display surface markers had been stimulated by the inducers but did not have sufficient time to complete expression of that marker. The results were consistent with the view that the cells in the starting population were distributed along a temporal expression pathway, and those which were first to express the earliest marker would also lead in the expression of a later marker. The order of expression was the same as that during normal megakaryocyte development.

Immunocytologic characteristics of mononuclear cell populations found in nonseptic olecranon bursitis.

OBJECTIVE: To determine the immunocytologic characteristics of the various subsets of nonseptic olecranon bursal fluid mononuclear cells. METHODS: Twenty consecutive patients with culture negative olecranon bursitis had immunocytochemical and flow cytometric analysis performed using a panel of monoclonal antibodies to determine lymphocyte and monocyte/macrophage population subtypes and proportions. RESULTS: In traumatic bursitis (n = 9), the mean (+/- SD) white blood cell (WBC) count/mm3 was 1,368 +/- 1,559; WBC mononuclear differential count was 29.5 +/- 19% lymphocytes and 55 +/- 26% monocyte/macrophages. In idiopathic bursitis (n = 11), the mean WBC/mm3 was 376 +/- 515; WBC mononuclear differential count was 28.5 +/- 16% lymphocytes and 52 +/- 27% monocytes/macrophages. Flow cytometry revealed 88% CD2+ T lymphocytes in the lymphocyte population, 3% B lymphocytes and CD4/CD8 T cell mean ratio of 2.5 +/- 1.5 for traumatic bursitis and 88% CD2+ T lymphocytes, 4% B lymphocytes and CD4/Cd8 ratio of 1.4 +/- 0.6 for idiopathic bursitis (p < 0.05, t test). Both groups contained increased proportions of lymphocyte subtypes expressing activation markers: CD25+, CD26+ and HLA DR+ compared to normal peripheral blood. In traumatic bursitis, the mean percent of CD14+ cells (monocyte/macrophages) was 62 +/- 24; in idiopathic bursitis, the mean percent was 51 +/- 28. The vast majority expressed high levels of HLA-DR indicating activation. CONCLUSION: We observed a preponderance of activated T cell subpopulations and monocyte/macrophages suggesting an immunologic role for these cell populations in the development and perpetuation of nonseptic bursitis.

Unusual oral presentation of non-Hodgkin's lymphoma in association with HIV infection.

In 4.4% of human immunodeficiency virus-associated non-Hodgkin's lymphoma the presenting lesion is seen in the mouth. Often the lesion may clinically resemble a less sinister process, and a definitive diagnosis of lymphoma may be delayed. We describe three unusual cases of non-Hodgkin's lymphoma, appearing intraorally in association with other oral lesions, in HIV-positive homosexual men. The three patients reported here were all diagnosed as having diffuse, large-cell malignant non-Hodgkin's lymphoma. We performed Epstein-Barr virus DNA in-situ hybridization on our cases and Epstein-Barr virus DNA sequences were not seen. We review the pertinent literature and stress the importance of including non-Hodgkin's lymphoma in the differential diagnosis of oral lesions in patients at risk of HIV infection.

Oral presentation of Kaposi's sarcoma in a patient without severe immunodeficiency.

Primary oral Kaposi's sarcoma of the "traditional type" (non-African, non-acquired immunodeficiency syndrome, nonimmunosuppressed) is a rare disorder. Presentation of this disorder at this site has not been well documented in the surgical pathology literature. This report describes a primary oral Kaposi's sarcoma in an older man without evidence of the acquired immunodeficiency syndrome or overt immunosuppression; this sarcoma recurred three times before a correct diagnosis was made. The case illustrates the importance of including Kaposi's sarcoma in the differential diagnosis. The lesions can easily be confused with pyogenic granuloma if the physician is unaware that primary Kaposi's sarcoma can occur at this site.

Morphology and histochemistry of infant testes in the prune belly syndrome.

Testicular biopsy samples from 3 boys 5.5, 6 and 7 months old with the prune belly syndrome and intra-abdominal testes were examined morphologically and phenotypically for the presence of alkaline phosphatase. Findings were compared with those in age-matched autopsy controls. All patient specimens demonstrated atypical germ cells with large nuclei and prominent nucleoli, and intense alkaline phosphatase staining localized to the cytoplasmic membrane. The presence of these testicular abnormalities suggests that a developmental arrest is fundamental to the pathogenesis of the undescended testes associated with the prune belly syndrome. The similarity of the histological appearance of these testes to that of intratubular germ cell neoplasia suggests that long-term followup of these patients for the development of invasive germ cell tumors is important.

Paneth-like cells in an adenoma and adenocarcinoma in the ampulla of Vater.

A case of adenocarcinoma with significant Paneth cell differentiation arising in a villoglandular polyp at the ampulla of Vater is presented. Paneth-like cells, containing distinct fuchsinophilic granules, were a prominent component of the nonglandular invasive adenocarcinoma and were also seen in the associated adenomatous polyp. Lysozyme, trichrome, and periodic acid-Schiff digest stains, and electron microscopy confirmed that the granules were lysosomal in nature. This case confirms that cells with Paneth-like features can be a significant component in invasive neoplasms and can occur at unusual sites such as the ampulla of Vater.

Disseminated dermal dendrocytomas. A new cutaneous fibrohistiocytic proliferative disorder?

A 77-year-old white woman presented with 1 1/2-year history of progressively enlarging cutaneous papules, nodules, and plaques, some of which had spontaneously regressed. Her past medical history included untreated chronic lymphocytic leukemia for 10 years' duration. Multiple skin biopsy specimens revealed a diffuse superficial and deep dermal spindle-cell infiltrate accompanied by occasional foamy round cells and multinucleated giant cells. The spindle-shaped cells were focally arranged in a storiform pattern with prominent fibrous stroma. The spindle-shaped cells stained positively for numerous macrophage markers including CD45, factor XIIIa, Leu M5, HLA-DR, CD4, and Leu M3, consistent with dermal dendrocytes. They were also positive for nonspecific esterase and acid phosphatase, which is typical of tissue macrophages. The spindle-shaped cells were negative for CD-1, S-100, and ATPase activity, thus excluding a Langerhans cell immunophenotype. Combining the clinical features, light microscopy, immunohistochemistry, and enzymatic analysis, this patient appears to represent a novel cutaneous fibrohistiocytic proliferative disorder that features large numbers of dermal dendrocytes.

Primary central nervous system lymphomas: natural history and response to radiation therapy in 55 patients with acquired immunodeficiency syndrome.

The incidence of primary central nervous system (CNS) lymphoma has increased rapidly in patients with acquired immunodeficiency syndrome (AIDS) and is predicted to exceed 1800 cases annually by 1991. To characterize the natural history and response to radiation therapy (RT) of these lesions, the authors have reviewed the clinical histories of 55 AIDS patients with biopsy-proven primary CNS lymphomas. The tumors responded both clinically and radiologically to whole-brain RT consisting of 4000 rad in 267-rad fractions over 3 weeks or an equivalent neuroret dose. The mean duration of survival from the appearance of symptoms consistent with the mass lesion was significantly greater in patients who received RT than in those who did not (42 vs. 134 days, p less than 0.5; median 27 vs. 119 days). Autopsy findings showed that patients who did not receive RT died from tumor progression, whereas those who completed RT died of opportunistic infections. Patients with AIDS who are suspected of having primary CNS lymphoma should therefore immediately undergo biopsy and, if the diagnosis is confirmed, whole-brain RT. With early diagnosis and treatment, these tumors respond to, and patients benefit from, RT. Survival of such patients may in future be prolonged by more effective treatments for systemic opportunistic infections.