Oral Paracoccidioidomycosis Granulomas are Predominantly Populated by CD163+ Multinucleated Giant Cells.

Multinucleated giant cells (MGC) are considered to be a hallmark of granulomatous inflammation; thus, they may play an essential role in the host response against pathogens, particularly Paracoccidioides brasiliensis. This study characterizes the MGC found in oral paracoccidioidomycosis and assesses the correlation of MGC with the amount of fungi within oral tissues. Twenty-six cases were included. They were classified as loose or dense granulomas, and the total MGC, including foreign-body and Langhans giant cells, besides the total and intracellular fungi, were taken into consideration. CD163 immunoexpression was performed, and CD163+ multinucleated giant cells were also quantified. Dense granulomas revealed more foreign-body type and total giant cells than loose granulomas (P < 0.05). Total giant cells showed a positive linear correlation with the CD163+ cells (P = 0.003; r = 0.56) and intracellular fungi quantification (P = 0.045; r = 0.40). Oral paracoccidioidomycosis lesions contain MGC that mainly belong to a CD163+ phenotype, also showing both Langhans and foreign-body arrangements. Additionally, the higher the presence of MGC, the higher the amount of phagocytized fungi.

E-cadherin is expressed by mono- and multinucleated histiocytes in cutaneous sarcoidal and foreign body granulomas.

E-cadherin, a member of the cadherin family of transmembrane adhesion receptors, is critical for cutaneous barrier function, as it promotes keratinocyte and Langerhans cell adhesion in the epidermis. Recent murine models of chronic inflammation identified new E-cadherin expressing subsets of mononuclear phagocytes, including alternatively activated macrophages and selected inflammatory dendritic cells. It has been shown in vitro that expression of E-cadherin by murine macrophages promotes their homotypic aggregation and fusion to multinucleated giant cells (MNGCs), a signature cell type of granulomatous inflammation. The purpose of this study was to assess E-cadherin expression on histiocytes and giant cells in cutaneous granulomas in humans. E-cadherin expression was evaluated by immunohistochemistry of formalin-fixed paraffin-embedded skin biopsies of foreign body granulomas (n = 21) and sarcoidosis (n = 21). The results showed consistent membranous E-cadherin staining pattern on mononucleated histiocytes and MNGCs in both granuloma types. These E-cadherin expressing histiocytes are distinct from dermal Langerhans cells because they lacked CD1a expression. Our findings suggest that E-cadherin expressing mononuclear histiocytes are likely precursors for MNGCs in cutaneous granulomas and may play a critical role in disease pathogenesis.

StarD7 behaves as a fusogenic protein in model and cell membrane bilayers.

StarD7 is a surface active protein, structurally related with the START lipid transport family. So, the present work was aimed at elucidating a potential mechanism of action for StarD7 that could be related to its interaction with a lipid-membrane interface. We applied an assay based on the fluorescence de-quenching of BD-HPC-labeled DMPC-DMPS 4:1 mol/mol SUVs (donor liposomes) induced by the dilution with non-labeled DMPC-DMPS 4:1 mol/mol LUVs (acceptor liposomes). Recombinant StarD7 accelerated the dilution of BD-HPC in a concentration-dependent manner. This result could have been explained by either a bilayer fusion or monomeric transport of the labeled lipid between donor and acceptor liposomes. Further experiments (fluorescence energy transfer between DPH-HPC/BD-HPC, liposome size distribution analysis by dynamic light scattering, and the multinuclear giant cell formation induced by recombinant StarD7) strongly indicated that bilayer fusion was the mechanism responsible for the StarD7-induced lipid dilution. The efficiency of lipid dilution was dependent on StarD7 electrostatic interactions with the lipid-water interface, as shown by the pH- and salt-induced modulation. Moreover, this process was favored by phosphatidylethanolamine which is known to stabilize non-lamellar phases considered as intermediary in the fusion process. Altogether these findings allow postulate StarD7 as a fusogenic protein.

Giant cell collagenoma: case report and review of the literature.

BACKGROUND: Giant cell collagenoma (GCC) is a recently described cutaneous fibrous neoplasm that usually affects young to middle-aged adults. Despite its similar histological appearance with circumscribed storiform collagenoma, no association of GCC with Cowden's syndrome has been described so far. To the best of our knowledge only five cases of this rare fibrous tumor have been reported so far. METHODS: We report a case of a 79-year-old male patient presenting with a slow growing flesh-colored dome-shaped lesion in his left forearm, with a clinical diagnosis of fibroma. No stigma of Cowden's syndrome was depicted. RESULTS: The histological analysis showed a symmetrical and well-circumscribed flat-dome-shaped lesion covered by an atrophic overlying epidermis. The neoplasm was composed of hyalinized collagen bundles disposed in a whorled storiform pattern. Admixed with the collagen matrix, there were two distinct cell populations, one composed by spindle-shaped mononuclear cells, and the other composed by bizarre multinucleated giant cells. Immunohistochemical analysis showed positivity for vimentin and actin HHF35 in the mononucleated. The multinucleated cells only immunoexpressed vimentin. CONCLUSION: GCC is an unusual cutaneous fibrous tumor that should be differentiated from circumscribed storiform collagenoma, pleomorphic fibroma, regressive forms of dermatofibroma, and solitary myofibroma based on its histological features.

Pleomorphic xanthoastrocytoma: report of a case diagnosed by intraoperative cytopathological examination.

The authors present an unusual case of a 13-yr-old boy with a 3-mo history of seizures. A CT scan showed a contrast-enhancing mass located in the left temporal lobe. The patient underwent a stereotatic-guided craniotomy; intraoperative cytological diagnosis was performed by the smear technique, showing a pleomorphic xanthoastrocytoma. The tumor was totally resected. Definitive diagnosis was established by examination of paraffin-embedded material. Six months after the surgical intervention, the patient is doing well, with no radiological evidence of recurrence. The cytological differential diagnosis of giant cell lesions of the central nervous system is emphasized.

[Pneumatosis intestinalis. Report of 3 cases]. / Neumatosis intestinal. Informe de tres casos.

OBJECTIVE: To describe the clinical, radiological, morphological, and immunohistochemical characteristics of three cases of pneumatosis intestinalis. METHODS: From 1982 to 1999, cases diagnosed as pneumatosis cystoides intestinalis were reviewed. The laboratory results, X-ray findings, clinical course, treatment and evolution were obtained from the clinical charts. Slides and macroscopic photos were obtained from the surgical pathology files. New slides were obtained from the paraffin blocks for immunohistochemical detection of endothelial cells (CD 31) and macrophagic cells (CD 68). RESULTS: We found three patients with pneumatosis intestinalis associated to a history of abdominal surgeries from 936 enteral resections (0.3%). These three patients showed clinical features of intestinal obstruction. Morphological and immunohistochemical analysis showed pseudocysts without an epithelial and endothelial lining. Some spaces were lined by multinucleated giant cells positive for CD 68 and endothelial cells that were CD 31 positive. CONCLUSIONS: Antecedent of obstruction and abdominal surgeries were the constant association with pneumatosis cystoides intestinalis. Most lesions were pseudocysts without epithelial or endothelial lining.

Immunocytochemical study of giant cell fibroma.

Giant cell fibroma (GCF) is a non-neoplastic lesion of the oral mucosa. The origin of stellate and multinucleate cells of GCF is not well known. The purpose of the present article was to investigate the immunoreactivity of these cells for leukocyte common antigen, vimentin, tryptase, HLA-DR, alpha-smooth muscle actin, CD68, and S-100. The results showed positive staining only for vimentin. This suggests that the stellate and multinucleate cells of GCF have a fibroblast phenotype.

Peripheral giant cell granuloma. An immunohistochemical and ultrastructural study.

OBJECTIVE: To study the nature of multinucleated and mononuclear cells from peripheral giant cell granuloma (PGCG). MATERIALS AND METHODS: Formalin-fixed, paraffin-embedded sections of 40 cases of PGCG were immunohistochemically stained for vimentin, alpha I-antichymotrypsin, CD68, S-100 protein, lysozyme, leucocyte common antigen (LCA), factor VIII-related antigen and muscle cell actin. Six cases of PGCG were also studied by transmission electron microscopy. RESULTS: Vimentin, alpha I-antichymotrypsin and CD68 were expressed in both the mononuclear and multinucleated giant cells. Dendritic mononuclear cells, positive for S-100 protein, were noted in 67.5% of the lesions, whereas lysozyme and leucocyte common antigen were detected in occasional mononuclear cells. Ultrastructural examination showed mononuclear cells with signs of phagocytosis and sometimes interdigitations with similar cells. Others presented non-specific characteristics and the third type exhibited cytoplasmic processes and occasional Birbeck granules. Some multinucleated giant cells showed oval nuclei, abundant mitochondria and granular endoplasmic reticulum whereas others presented with irregular nuclei and a great number of cytoplasmic vacuoles. CONCLUSIONS: Immunohistochemical and ultrastructural results suggest that PGCGs of the jaws are composed mainly of cells of the mononuclear phagocyte system and that Langerhans cells are present in two thirds of the lesions.

Atypical stromal giant cells of cervix uteri--evidence of Schwann cell origin.

The report describes atypical multinucleated giant cells adjacent to proliferated nerve fascicles in a circumscribed subepithelial area of the cervix uteri of a 44-year-old multipara. Ultrastructural examination revealed cytoplasmatic processes, basal lamina, intracytoplasmic microfibrils, bizarre nuclear shapes with pseudoinclusions and nuclear fragments connected by small chromatin bridges (nucleotesimals). Immunohistochemical examination showed positive staining for vimentin and S-100 protein. Quantitative topography exhibited an isotropic distribution of the giant cells in an anisotropic architecture of mononuclear cells. A Schwann cell origin of the atypical giant cells is postulated. Aetiopathogenetically the lesion is regarded to be due to a trauma during delivery followed by regenerative proliferation of nerve fascicles and degenerative alterations of proliferating Schwann cells. The knowledge of this lesion is considered important, because the atypical cells could be confounded with malignant neoplastic cells.