Juvenile xanthogranuloma. Clinical and pathologic characterization

The changing name of the juvenile xanthogranuloma bears witness to the evolution of knowledge and experience of its varied clinical and histologic presentations. This study characterizes the clinical, microscopic, and some immunohistochemical features of 34 cases. The salient clinical findings include a bimodal age distribution inclusive of adults, a male:female ratio of 4:1, occasional multiplicity of lesions (20%), and common presentation in the cephalad area. Histologic findings include varied architectural patterns, cellular participation in various proportions by foamy histiocytes, epithelioid monocytes, lymphocytes, plasma cells, eosinophils, Touton giant cells, and spindle cells of two forms (dendritic and fusiform). S100-positive dendritic cells comprised a minor, but important, component at expansion zones. The significance of these findings is described.     

Ultrastructural and immunocytochemical studies of enamel tufts in human permanent teeth.

Enamel tufts were exposed after decalcification of the enamel matrix and their fine structures and immunocytochemical characteristics were examined. Under the binocular microscope and the scanning electron microscope (SEM), enamel tufts appeared as corrugated ribbon-like structures located on the dentine parallel to the tooth axis. SEM observation disclosed enamel tufts as bundles of well extended tubular structures with cross striations attributable to hypocalcified enamel sheaths. Plate-like structures were observed at the center of enamel tufts, where they ran parallel to the enamel tufts. Under the transmission electron microscope (TEM), the plates of tufts revealed their origin in the superficial layer of the dentine, penetrating the hypercalcified zone adjacent to the dentine-enamel (D-E) junction, and then reaching the tuft region. The plates of tufts ran mainly along the enamel sheaths and partially across the prisms in the tuft region. THe protein-A-gold technique revealed an intense immunoreactivity for amelogenin over the superficial layer of the dentine, but over the enamel prisms in the tufts nor over the plates of tufts. The immunoreactivity for 13-17 kd protein was detected over the filamentous structures closely associated with the enamel sheaths in the enamel tuft. Thus our study disclosed that enamel tufts consist of both well extended hypocalcified enamel prisms and plates of tufts. The major organic component of the enamel tufts is suggested to be 13-17 kd protein rather than amelogenin.     

Juvenile xanthogranuloma of the nasal cavity

JXG is a benign lesion of unknown incidence. It is the most frequent type of non-langerhans histiocytosis with a median age of 2 years. It usually presents as isolated cutaneous lesions. Multiple lesions, especially over the head and neck, may occur. The skin lesions tend to regress slowly with time. Extra-cutaneous and visceral involvements have been observed, the most common site being the eye. When the lesions are numerous, they may persist, hence the need for treatment with corticosteroids or chemotherapy. Histologically, the lesion consists of histiocytes admixed with an inflammatory infiltrate of variable density. The lesions are initially monomorphic and very cellular, progressively enriched with multinucleated giant cells of Touton and foamy cells, followed by spindle cells. We report an 8-year old girl with JXG of early type without multinucleated and foamy cells. This case presented as a tumour in the inferior meatus of nasal cavity, clinically simulating a rhabdomyosarcoma. This atypical clinical and histological presentation with benign evolution should be recognized since it requires only local treatment.     

Ultrastructural and immunocytochemical observations on angiosarcomas

Forty-seven angiosarcomas have been studied by light and electron microscopy. Neoplastic endothelial cells do not consistently display specific ultrastructural features, but certain aspects of the fine structure of the cells and their arrangement can be useful to establish or confirm the diagnosis. Experience with the common endothelial cell markers as diagnostic aids is briefly reviewed.     

Ultrastructural and immunocytochemical studies of the viscacha (Lagostomus maximus maximus) pituitary pars tuberalis

The hypophyseal pars tuberalis (PT) has been the focus of numerous studies attempting to understand its physiological role in the reproductive regulation and modulation by the neuroendocrine system. Ultrastructural studies of the PT in a number of species have shown that it consists of a well-developed hypophyseal area with important secretory activity, demonstrated by the abundance of secretory granules in the cytoplasm and the marked blood irrigation. This article describes ultrastructural and immunocytochemical aspects of the PT in viscachas captured in their habitat. The cell types identified were PT-specific cells, agranulated cells, and Folliculostellate cells. PT-specific cells are divided into type I and II. Type I cells have cytoplasms with secretory granules of 150-500 nm diameter. The secretory granules of type II PT-specific cells are 65-200 nm in diameter. Both cellular types exhibit numerous nerve endings on the plasmatic membranes. Agranulated cells exhibit nuclei with lax chromatin, mitochondria, phagosomes, scarce Golgi complex, and rough endoplasmic reticulum. Folliculostellate cells exhibit an irregularly shaped and moderately condensed nucleus. All the described cellular types exhibit deposits of cytoplasmic glycogen. The immunocytochemical study revealed the presence of cells immunostained for LH-beta and FSH-beta in the PT caudal zone. ACTH was only detected in the zona tuberalis. No staining was observed with antiprolactin, anti-TSH-beta, and anti-GH sera. Folliculostellate cells exhibited staining with anti-S-100. The results demonstrate that the viscacha PT is a hypophyseal zone with specific cellular types, which exhibits evident secretory activity. The presence of nerve endings suggests neural control of the function of PT cells.     

Ultrastructural spectrum of medulloblastoma with immunocytochemical correlations

Electron microscopy was used to examine 72 cases of medulloblastoma to better characterize the ultrastructural spectrum of this tumor. Twenty-four cases showed prominent neural differentiation. Twenty-three cases showed minimal (21) or no (2) recognizable neural differentiation, and the remainder of the cases (25) showed intermediate differentiation. All 42 cases tested stained for neuron-specific enolase, 28 for synaptophysin, and 12 for neurofilament protein. All cases showed strong reactivity for glial fibrillary acidic protein (GFAP) within reactive astrocytes. Three cases showed reactivity for GFAP within tumor cells. Medulloblastoma exhibits a broad spectrum of neural differentiation, with nearly all cases showing at least some degree of this change, and it universally exhibits participation of reactive astrocytes which can create a potential for diagnostic confusion.     

Ultrastructural and immunocytochemical characterization of circulating mononuclear cells in patients with myelomatosis.

The ultrastructure of blood mononuclear cells from two IgG myeloma patients was studied, and cells reacting with anti-idiotypic serum and polyspecific anti-Ig serum were characterized by immunoperoxidase techniques. Abnormal, mononuclear cells were present in the blood of both patients, which morphologically were classified as atypical small to medium-sized lymphocytes, polymorphic immature lymphocytes (lymphoblasts), predominantly of the lymphoplasmocytic type and atypical, plasmocytic cells or myeloma cells. Immunocytochemical observations showed that most of the abnormal cells, including atypical small to medium-sized lymphocytes, reacted with anti-idiotypic and polyspecific anti-Ig serum. Periods of relapse and remission were correlated with an increase and decrease, respectively, of the number of abnormal cells and cells which reacted with anti-idiotype and anti-Ig serum. The observations indicate that circulating lymphoid cells are part of the myeloma clone.     

Ultrastructural, immunocytochemical, and cytogenetic characterization of a large congenital fibrosarcoma.

Cytogenetic, immunocytochemical, and ultrastructural studies were performed on a large congenital fibrosarcoma. To our knowledge, this is the first report of a congenital fibrosarcoma characterized by all of these techniques. The findings of immunochemical and electron microscopic studies supported the suggestion that the tumor is of fibroblastic origin. The karyotype of the tumor (48,XY,+11,+20) is similar to that observed in previously reported cases and substantiates the hypothesis that congenital fibrosarcoma is characterized by nonrandom gain of chromosomes.     

Ultrastructural and immunocytochemical study on normal human palmar aponeuroses

Background: Human palmar aponeurosis can be affected by a fibrotic process whose aetiopathology is unknown. As the organization of that normal tissue has not been completely investigaged, the aim of the present study was to define the ultrastructure of the aponeurosis in order to better understand its biology and behaviour in pathology. Methods: Bioptic samples from normal subjects of different ages were analyses by optical and electron microscopy and by immunocytochemistry. Results: The aponeurotic branches consisted of thick, almost parallel collagen bundles containing columns of prominent cells, characterized by long cytoplasmic projections. Cells did not change in number and distribution with age and appeared longer and slighter in the old than in the young subjects. They exhibited plasma membrane almost completely decorated by pinocytic vesicles, intracytoplasmic bundles of thin filaments with zonal thickenings close to the cell membrane, and well-developed subcellular structures. Cells expressed smooth muscle cell α-actin, as revealed by immunostaining. The external surface of the plasma membrane was underlined by a discontinuous basement membrane–like structure and by a thick coat of interwoven filaments, highly positive to hyaluronan-recognizing antibodies. Immunocytochemical analyses revealed that collagen fibrils were positive for collagen types I, III, and VI and that elastin fiber composition was rather complex. Conclusions: Independently of the age, normal palmar aponeurotic cells show peculiar morphological features and peculiar cell-matrix interactions, very likely mediated by hyaluronan. These findings indicate that normal aponeurotic cells cannot be regarded as typical tenocytes and suggest the need for a better definition of their phenotype in order to understand their behaviour in pathological processes. © 1994 Wiley-Liss, Inc.     

Ultrastructural and immunocytochemical study of a case of invasive cribriform breast carcinoma.

A case of recurrent invasive cribriform carcinoma of the breast mimicked the histological and mucin staining characteristics of adenoid cystic carcinoma. The diagnosis was based on negative immunocytochemical staining for laminin and ultrastructural evidence of luminal differentiation by cells lining the cystic spaces. Accurate characterisation of this type of breast tumour can be facilitated by retrospective immunocytochemical or ultrastructural examination, or both.     

Histopathological and immunocytochemical studies of Trypanosoma musculi infection of mice.

Mice infected with Trypanosoma musculi developed hyperplasia of the spleen, lymph nodes, and liver; in contrast, their thymuses displayed transient involution. All organs returned to normal in a month or less. There was modest anemia, lasting until the parasites were cleared from the bloodstream, followed by a rapid influx of erythrocytes into the blood and a subsequent return to normal erythrocyte numbers. During the first 2 weeks, trypanosomes and trypanosome-derived substances were found in the livers and, in moderate amounts, in the red pulp of the spleens; thereafter, trypanosomes and trypanosome-derived substances gradually decreased in these organs. The lymphoreticular hyperplasia involved a large increase of immunoglobulin G (IgG)-containing cells in the spleens and lymph nodes at 2 weeks of infection. Hyperplasia of immunoglobulin-producing cells correlated with elevation of serum immunoglobulins, especially IgG. Cells producing IgG in the spleens proliferated mainly around the central arterioles of the white pulp, i.e., in the T-cell-dependent areas. The decline of trypanosome-derived substances in the livers and spleens was associated with marked hyperplasia of IgG-containing cells in the spleens and lymph nodes. These results suggest that trypanosome-mediated depression of murine immune responses is attributable to proliferation and terminal differentiation of more-mature lymphoid cells and temporary inhibition of normal maturation of less-mature precursor cells.     

Juvenile xanthogranuloma developing after treatment of Langerhans cell histiocytosis: case report and literature review

The synchronous or metachronous development of Langerhans cell histiocytosis and non-Langerhans cell histiocytosis in the same patient is rare. To date, only seven cases of xanthogranulomas developing in young patients with a history of Langerhans cell histiocytosis and systemic therapy have been reported in the literature. As of yet, the pathogenesis and the clinical significance of this phenomenon are unclear. We report the case of a 3 year old boy who developed juvenile Xanthogranulomas on the forehead and right upper eye lid 1.5 years after systemic therapy for monosystemic Langerhans cell histiocytosis of the bone and complete disease remission.     

Ultrastructural immunocytochemical localization of enkephalin in the goldfish preoptic nucleus

The ability of membrane perturbing drugs to inhibit the specific binding of [3H]/B4101 (2,6-dimethoxyphenoxyethyl)aminomethyl-1,4-benzodioxane) to the alpha 1-receptor of beef cortical membranes was determined. Except for quinidine and phenytoin, the IC50 for inhibition of specific [3H]WB4101 binding to the alpha 1-receptor correlated with the membrane/buffer partition coefficient of the drug. Almost all of the drugs inhibited specific ligand binding at concentrations approaching those reported necessary to stabilize membranes although both activities correlate well with reported membrane/buffer partition coefficients. The results suggest that specific receptor function can be modified by drug perturbation of the lipid microenvironment of the receptor macromolecule.