Search results for "Histogenesis"
showing 10 items of 36 documents
Experimental models of kidney tumors.
1993
We here present in outline some outstanding results on the animal models of renal tumors submitted to the highest attention, which include two kinds of epithelial neoplams: those developed from the epithelium lining each the renal tubules (renal cell tumors) and pelvis; the mesenchymal tumor of rat; and tumors with embryonal appearance: the nephroplastoma as well as the variant of it known as the estrogen-induced tumor in the hamster. The review deals with methods for tumor induction and the pathobiology of tumors, the latter mainly focussed on the indendification of the precise types of renal cells committed in tumor origin. The existence of closely related counterparts of these animal tum…
Malignant fibrous histiocytoma of the renal capsule
1981
We report about an extremely rare case of malignant fibrous histiocytoma (MFH) of the renal capsule. The tumor is composed of fibroblast-like cells arranged in a storiform pattern and histiocyte-like cells with multinucleated giant cells, both showing no iron reaction. Characteristic of the histiocytic quality of the tumor are numerous PAS-positive intracytoplasmic droplets which can be identified as erythrophagosomes only under the electron microscope. Emphasis is put on the preoperative differential diagnosis of the tumor from renal cell carcinoma as well as on its histogenesis and prognosis.
Immunohistochemistry of primary central nervous system malignant rhabdoid tumors: report of five cases and review of the literature
1996
Malignant rhabdoid tumors (MRT) are characterized by a typical light microscopic morphology with uniformly round tumor cells, vacuolated cytoplasm with occasional round, hyaline intracytoplasmic, periodic acid-Schiff-positive inclusions, vesicular nuclei with prominent nucleoli and positive immunoreactivity for vimentin. The histogenesis of MRT is controversial. Five cases of primary central nervous system (CNS) rhabdoid tumors in children are presented. Immunohistochemical, light and electron microscopic features are compared with primary CNS malignant rhabdoid tumors reported in the literature. Expression of various neurofilaments in our cases of primary CNS rhabdoid tumors was prominent …
Osteonectin Expression in Odontogenous and Non-odontogenous Tumors and Tumor-like Lesions of the Skull and Jaw Bones
1988
The organic matrix of osseous and odontogenic tissues is formed mainly by collagen type I. In addition there is a considerable bulk of noncollagenous proteins (Prince et al. 1987) in bone among which osteonectin represents the greatest amount. This protein, first isolated by Termine et al. (1981) has a molecular weight of 29 kD and possibly is involved in the mineralization process of collagenous fibrils in bone (Romberg et al. 1985). Recently osteonectin could be demonstrated in bone tumors and normal bone and has been considered as a marker for bone tumor cells (Schulz et al. 1985; Jundt et al. 1987). The aim of the present study was to examine the expression of osteonectin in odontogenou…
Vergleichende Untersuchungen �ber Morphologie und Histogenese des Seminoms und Disgerminoms
1951
An Hand eingehender morphologisch-histologischer Untersuchungen von Seminom und Disgerminom wird die Verwandtschaft beider Tumoren einer kritischen Stellungnahme unterzogen mit dem Ergebnis: 1. Seminom und Disgerminom sind morphologisch gleichartige Tumoren. 2. Als Mutterzelle mus die noch nicht geschlechtsspezifisch differenzierte Keimzelle aufgefast werden. 3. Seminome und Disgerminome sind keine Teratome, sie sind bestenfalls mit den Teratomen uber eine allen gemeinsame Mutterzelle verwandt.
Zur Histogenese des Epithelioma Malherbe und von seinen topischen Beziehungen zum Keratoakanthom
1965
Ausgehend von der Beobachtung Keratoakanthom-artiger Strukturanteile bei einem Epithelioma Malherbe und der Feststellung von “Schattenzellfeldern” bei einem von 20 daraufhin durchgemusterten Keratoakanthomen wird zur Histogenese der Malherbeschen Geschwulstform Stellung genommen, als deren Ausgangspunkt indifferent gebliebene Zellschichten der auseren Haarwurzelscheide unterhalb der Talgdruse—im Gegensatz zu dem Ursprung des Keratoakanthoms oberhalb der Talgdruseneinmundung — angesprochen werden. Trotz dieser topischen Nachbarschaftsbeziehungen zwischen Epithelioma Malherbe und Keratoakanthom handelt es sich bei beiden Epitheliomen um zwei im Endergebnis der Geschwulstentwicklung durchaus d…
Primordial odontogenic tumor: An immunohistochemical profile.
2017
Background Primordial Odontogenic Tumor (POT) is a recently described odontogenic tumor characterized by a variably cellular loose fibrous tissue with areas similar to the dental papilla, covered by cuboidal to columnar epithelium that resembles the internal epithelium of the enamel organ, surrounded at least partly by a delicate fibrous capsule. The purpose of this study was to investigate the possible histogenesis and biological behavior of this rare tumor by means of a wide immunohistochemical analysis of its epithelial and mesenchymal components. Material and Methods The immunoexpression of twenty-three different antibodies were evaluated in four cases of POT. Results The epithelial cel…
CHARACTERIZATION OF A NEW RAT CELL LINE ESTABLISHED FROM 2′AAF-INDUCED COMBINED HEPATOCELLULAR CHOLANGIOCELLULAR CARCINOMA
2001
A rat cell line-nominated CC-62 derived from a combined hepatocellular and cholangiocellular carcinoma obtained by administration of 2-acetylaminofluorene to male Wistar rats, has been established. Using light and electron microscopy it was determined that morphologically the tumor consisted of a mixed population of hepatocytes and cholangiolar neoplastic cells, intermingled with small, undifferentiated oval-like cells. The CC-62 line has been maintained through 90 passages in culture adopting a paving stone arrangement. Doubling time at the 12th passage was 23 h. Immunostaining with a panel of antisera was performed to identify the cytological profiles of the cell line. There was no k-ras …
Heterogeneity of intermediate filament expression in human testicular seminomas.
1990
Testicular seminoma has in the past been considered to represent a germ cell tumor incapable of further differentiation. In recent years this view has been challenged on the basis of morphologic and chromosomal studies. Moreover, studies of intermediate filaments (IF) of seminoma cells have provided evidence of the capability of seminoma cells to differentiate in different directions. In the present study of the IF protein profile of 26 human testicular seminomas, using frozen as well as formalin-fixed, paraffin-embedded tissues, we report evidence of a heterogeneous differentiation potential inherent in these neoplasms. Thus, in 4 of the seminomas neither cytokeratins nor vimentin were det…
Gliofibromas (including malignant forms), and gliosarcomas: a comparative study and review of the literature
1993
The presence of connective tissue elements in gliomas necessitates in every case a thorough analysis of the character and derivation of such elements to allow the formulation of an appropriate diagnosis. Four cases are presented in this paper. In cases 1 and 2 (anaplastic astrocytomas in two children, 9 and 4 years old, respectively) all the neoplastic elements were astrocytes and their ability to produce or indirectly promote the production of reticulin and collagen fibers accounted for the presence of such elements in close association with the tumor cells. The term "gliofibroma" has been coined for such tumors, but "desmoplastic astrocytoma", (low grade or anaplastic) or in highly malign…