Birbeck granules or Birbeck junctions? Intercellular "zipperlike" lattice junctions in eosinophilic granuloma of bone

Immunoelectron microscopic observation of chicken glucagon-like peptide (GLP)-1-containing cells in tissues derived from thin section, paraffin block and conventional method

The purpose of the present study was to investigate the possibility of immunoelectron microscopic observation of endocrine cells in paraffin-embedded tissues. The procedure, which involves reprocessing from sliced tissues and immunohistochemical staining by colloidal-gold immunolabeling of paraffin sections from paraffin blocks, was able to reveal the fine characteristics of secretory granules containing glucagon-like peptide-1. Morphometric analyses of the secretory granules showed no significant differences between the reprocessing procedure and a conventional post-embedding procedure, which was performed as a control. The reprocessing procedure has some advantages besides providing information on secretory granules containing the amino acid peptide. For example, the same cell can be observed under both a light microscope and the electron microscope. In addition, the high-electron densities of silver-enhanced gold particles are easily recognized, and the boundary between the profile of the granules and the immunogold labeling is clearly shown at the electron microscopic level. Furthermore, the procedure, which is inexpensive and does not require special devices, can effectively use precious samples that are already paraffin-embedded and unable to be obtained twice, such as the case for endangered animals and rare pathological tissues. To the best of our knowledge, the present study is the first to report the advantages of the reprocessing method for sliced paraffin sections of gut endocrine cells.

A structure resembling basal/external lamina on the surface of plasma cells, and a discussion on intercellular contacts between hemolymphoid cells

Basal/external lamina is not found over plasma cells or other hemolymphoid cells, and the feature can have diagnostic value in distinguishing the neoplastic counterparts of such cells from epithelium, endothelium, mesothelium, and so on, which do have this feature. In this paper, a material ultrastructurally indistinguishable from basal or external lamina is reported on reactive plasma cells found in a fibrous pseudotumor, intralobular stroma of normal breast, tumor stroma of squamous cell carcinoma, and submucosa of normal human small intestine. It was focal, followed the contours of the cell-surface membrane, was lightly textured, 40-80 nm thick, and separated from the plasma cell surface membrane by a clear space resembling a lamina lucida. Its function remains uncertain, although it may implement adhesion to other cells, as part of the immune functions that plasma cells and other hemolymphoid cells perform in the gut, for example, and elsewhere.

Expression of Fas ligand in Langerhans' cell histiocytosis: A case report of a boy with multisystem involvement

Previous reports of patients with Langerhans' cell histiocytosis have shown characteristics of osteolytic lesion, visceral involvement and organ dysfunction. We report a 2-year-old boy who was diagnosed as Langerhans' cell histiocytosis with a prominent hepatomegaly. X-Radiogram, computed tomography and magnetic resonance imaging revealed the osteolysis of the right iliac bone, the absence of the left eighth rib as well as the right mandible, and an enhancing mass in the left cerebellum. The data of radiography were highly suggestive of Langerhans' cell lineage. The presence of large CD1a-positive mononuclear cells associated with inflammatory cells in peripheral blood smear and bone marrow aspirate further confirmed the diagnosis. In addition, expressions of S100, CD25, CD68, CD80, CD86, and Fas ligand were identified on these cells by immunocytochemical staining. The results indicate that although these cells are activated Langerhans' cells, progression of the disease and the bone destruction could be mediated by the overt FasL expression of the cells.

Langerhans cell (eosinophilic) granulomatosis. A clinicopathologic study encompassing 50 years

We summarize our experience with 238 cases of Langerhans cell granulomatosis (LCG), 198 of whom were followed for a median period of 10.5 years. Our patients did well unless overtreated, and no deaths were attributed to the disorder itself. The disease may appear in unifocal or multifocal form, and treatment is based on this fact. Virtually all patients recovered completely except for occasional residual orthopedic problems or residual diabetes insipidus. Several of the patients underwent subsequent pregnancies without difficulty. The granulomas primarily occur in bone, but lung, skin, and lymph nodal involvement is not uncommon. Involvement of thyroid, thymus, and other sites is rare. The hallmark of the disease is the accumulation of Langerhans cells (LCs). We review the pathology of LCG by histology, electron microscopy, and immunolabeling. LCs originally were identified in squamous epithelium, but these cells are part of the widespread system of dendritic cells. The latter cells, which arise from CD34+ progenitors, are specialized and efficient antigen-presenting cells for T-cell-mediated immunity. In LCG, however, the major associated cells are not T cells, but mature eosinophils: hence the original name eosinophilic granuloma. Confusion about terminology has been based upon the scanty and rather crude pathology reports in the original literature. The term histiocytosis X was meant to cover a spectrum of three diseases--eosinophilic granuloma, Hand-Schüller-Christian disease (HSC), and Letterer-Siwe disease (LS)--but HSC and LS have no basis in pathology and hence the terms are meaningless. The term HSC has become a synonym for multifocal eosinophilic granuloma (LCG). The term LS has been used in reporting a number of benign, malignant, or unknown conditions. We prefer the term LCG to avoid confusion with the term histiocytosis X because there is evidence that the LC is not a member of the mononuclear phagocyte system and hence not a tissue macrophage, and because the use of the term "histiocyte" has become a convenience in much of the literature when reporting incompletely understood diseases.