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At least 865 records · Page 48Linked to original sources
PubMed1992

Ectomesenchyme of ameloblastic fibroma reveals a characteristic distribution of extracellular matrix proteins.

The distribution of collagens type I, IV and VI, procollagen type III and of undulin was studied in four cases of ameloblastic fibroma (AF). The ectomesenchyme of AF revealed an as yet unobserved organization of these extracellular matrix proteins with collagen type VI clearly predominating over collagen type I, procollagen type III and undulin, that showed a weak and amorphous distribution throughout the tumor stroma. Undulin, a glycoprotein that is associated with mature collagen fibrils and with differentiated tissues, was not detectable in the tumor stroma of AF except for a slow expression around capillaries and in areas with a high cellularity. We could demonstrate that the characteristics of extracellular matrix composition allowed a clear distinction between the ectomesenchyme of AF and the adjacent normal mesenchymal stroma. Due to the specific staining patterns it was possible to detect epithelial tumor islands outside the typical ectomesenchymal stroma. Our findings furthermore indicate that epithelial cells of AF invade the adjacent normal mesenchyme possibly inducing de novo formation of ectomesenchymal tumor stroma.

Child↗
PubMed1996

PCNA and Ki-67 immunoreactivity in multinucleated cells of giant cell fibroma and peripheral giant cell granuloma.

Immunohistochemical investigation of PCNA and Ki-67, two diverse nuclear proteins essential to the cell cycle, was undertaken in archival, formalin-fixed and paraffin-embedded specimens of giant cell fibroma (GCF) and peripheral giant cell granuloma (PGCG++). GCF multinucleated cell nuclei were mostly PCNA+, although there was variability in staining intensity. This indicates heterogeneity in nuclear PCNA metabolism of GCF multinucleated cells, and it is possible that the most intensely stained nuclei have passed through the cell cycle more recently compared to the less immunoreactive nuclei. However, the absence of Ki-67 immunoreactivity in GCF multinucleated cells, and absence of mitoses in GCF multinucleated cells, suggests that cell cycling in the absence of cytokinesis is not involved in GCF multinucleated cell formation. Alternatively, GCF multinucleated cells possibly form by fusion of mononuclear cells previously identified as fibroblasts, although this theory cannot be confirmed by the data presented in this study, and the histogenesis of GCF multinucleated cells remains unclear. In contrast, absence of either PCNA or Ki-67 immunoreactivity in PGCG multinucleated cells is consistent with an osteoclast lineage and formation from differentiated mononuclear cells.

Cell Cycle↗
PubMed1999

Collagenous fibroma (desmoplastic fibroblastoma) presenting as a parotid mass.

We describe the case of a 50-year-old man who was found to have a painless, slow-growing parotid mass of 10 months duration. At surgery, a well-delimited, lobulated 4x5-cm tumor was located on the deep lobe of the left parotid gland, adhering to the parotid sheath and masseteric fascia. Follow-up 6 years later has shown no evidence of recurrence. Cardinal morphologic features included multiple nodules of sparsely distributed stellate-or spindle-shaped fibroblasts within a collagenous or myxocollagenous stroma. Fascial involvement and entrapment of salivary gland were focally identified at the edges. Tumor cells were diffusely positive for vimentin with faint focal staining for alpha-smooth muscle actin. These findings satisfied the diagnostic criteria for collagenous fibroma (desmoplastic fibroblastoma). Ours represents the first report of this tumor type mimicking a parotid tumor.

Fibroma, Desmoplastic↗
PubMed1999

Central fibroma in the ascending ramus of the mandible. Case report.

A case of central fibroma involving the mandible in a 58 year old woman is described. There was slight swelling of the left cheek and bone-hard bulging was detected on palpation but the patient had not complained of the swelling. The lesion was removed under general anaesthesia and then examined histopathologically. There was no sign of recurrence eleven months after the operation.

Collagen↗
PubMed1982

Shope fibroma virus. II. Role of the virion-associated nucleases.

The effect of Shope fibroma virus (SFV) infection on host DNA synthesis was investigated. The cytocidal strain, SFV-I, inhibited the incorporation of [3H]thymidine into nuclear DNA very shortly (2 h) after infection, whereas the noncytocidal strain, SFV-W, did so later (10 h postinfection) and to a lesser extent. Furthermore, a two- to threefold stimulation of host DNA synthesis was recorded in SFV-W-infected cells 3 to 4 h after infection. Since virion-associated nucleases have been implicated in the shutoff of host synthesis, these and other enzymatic activities were measured in purified virion preparations. The SFV strains and vaccinia virus contained equivalent amounts of DNA-dependent RNA polymerase, ATPase, and protein kinase activities. However, in SFV-W the pH 4.5 exonuclease activity was lower than in SFV-I and vaccinia virus, and the level of pH 7.8 endonuclease was almost undetectable. To test whether the lack of endonucleolytic activity had some effect on the removal of the cross-links in the parental DNA that occurs after viral penetration, the fate of the virion SFV DNA was followed. The majority (80%) of the SFV-I and SFV-W DNA molecules extracted after viral adsorption sedimented in alkaline sucrose gradients as cross-linked. After 3 h of infection, 75% of the SFV-I DNA molecules lacked cross-links, whereas 78% of the SFV-W DNA still remained cross-linked. The same results were obtained when the presence of cross-links was tested in restriction fragments. Taken together, these results indicate that virion-associated nucleases are involved in the early shutoff of host DNA synthesis and in the elimination of cross-links from the parental viral DNA.

Animals↗
PubMed1982

Shope fibroma virus. I. Biological and molecular properties of a cytocidal and a noncytocidal strain.

The biological and molecular properties of two strains of Shope fibroma virus (SFV) were compared. SFV-I was highly cytocidal to most of the cell lines tested and produced pocks in the chorioallantoic membrane of chick embryos. By contrast, SFV-W did not produce cytopathic effects in any of the cell lines or in the chorioallantoic membrane, but it induced characteristic foci 3 to 4 days after infection. Both strains produced tumors when inoculated into the skin of susceptible rabbits. Maximal infectivity in BSC-1 cells was reached by both strains between 24 to 48 h after inoculation. Viral DNA synthesis also took place at the same time, although cells infected with SFV-I incorporated three times more [(3)H]thymidine than cells infected with SFV-W. Sedimentation analysis and hydroxylapatite chromatography of the two viral DNAs indicated that their molecular weights were similar and that both were naturally cross-linked. Digestion with three restriction endonucleases, however, revealed that they had different restriction sites. When SFV-I and vaccinia DNA were compared, the restriction patterns were more alike. Analysis of the virion structural proteins by gel electrophoresis indicated that SFV-I, SFV-W, and vaccinia virus had many polypeptides in common, although there were distinctive differences among the three viruses. Finally, the results of plaque neutralization tests with different antisera showed that SFV-I and SFV-W shared common antigens and that vaccinia antiserum inhibited SFV-I but not SFV-W. We conclude that the SFV-I genome contains information for both cytolysis and tumorigenesis. This unusual virus may be a recombinant between an orthopoxvirus and a leporipoxvirus.

Animals↗
PubMed1986

Identification and nucleotide sequence of the thymidine kinase gene of Shope fibroma virus.

The thymidine kinase (TK) gene of Shope fibroma virus (SFV), a tumorigenic leporipoxvirus, was localized within the viral genome with degenerate oligonucleotide probes. These probes were constructed to two regions of high sequence conservation between the vaccinia virus TK gene and those of several known eucaryotic cellular TK genes, including human, mouse, hamster, and chicken TK genes. The oligonucleotide probes initially localized the SFV TK gene 50 kilobases (kb) from the right terminus of the 160-kb SFV genome within the 9.5-kb BamHI-HindIII fragment E. Fine-mapping analysis indicated that the TK gene was within a 1.2-kb AvaI-HaeIII fragment, and DNA sequencing of this region revealed an open reading frame capable of encoding a polypeptide of 176 amino acids possessing considerable homology to the TK genes of the vaccinia, variola, and monkeypox orthopoxviruses and also to a variety of cellular TK genes. Homology matrix analysis and homology scores suggest that the SFV TK gene has diverged significantly from its counterpart members in the orthopoxvirus genus. Nevertheless, the presence of conserved upstream open reading frames on the 5' side of all of the poxvirus TK genes indicates a similarity of functional organization between the orthopoxviruses and leporipoxviruses. These data suggest a common ancestral origin for at least some of the unique internal regions of the leporipoxviruses and orthopoxviruses as exemplified by SFV and vaccinia virus, respectively.

Base Sequence↗
PubMed1986

DNA sequence homology between the terminal inverted repeats of Shope fibroma virus and an endogenous cellular plasmid species.

DNA hybridization experiments indicate that the genome of a tumorigenic poxvirus. Shope fibroma virus (SFV), possesses sequence homology with DNA isolated from uninfected rabbit cells. Southern blotting experiments, either with high-complexity rabbit DNA as probe and SFV restriction fragments as targets or with high-specific activity, 32P-labeled, cloned SFV sequences as probes and rabbit DNA as target, indicate that the homologous sequences map at two locations within the viral genome, one in each copy of the terminal inverted repeat sequences. Unexpectedly, Southern blots revealed that the homologous host sequences reside in a rabbit extrachromosomal DNA element. This autonomous low-molecular-weight DNA species could be specifically amplified by cycloheximide treatment and was shown by isopycnic centrifugation in cesium chloride-ethidium bromide to consist predominantly of covalently closed circular DNA molecules. DNA sequencing of pSIC-9, a cloned 1.9-kilobase fragment of the rabbit plasmid species, indicated extensive homology at the nucleotide level over a 1.5-kilobase stretch of the viral terminal inverted repeat. Analysis of open reading frames in both the plasmid and SFV DNA revealed that (i) the N-terminal 157-amino acid sequence of a potential 514-amino acid SFV polypeptide is identical to the N-terminal 157 amino acids of one pSIC-9 open reading frame, and (ii) a second long pSIC-9 open reading frame of 361 amino acids, although significantly diverged from the comparable nucleotide sequence in the virus, possessed considerable homology to a family of cellular protease inhibitors, including alpha 1-antichymotrypsin, alpha 1-antitrypsin, and antithrombin III. The potential role of such cellular plasmid-like DNA species as a mediator in the exchange of genetic information between the host cell and a cytoplasmically replicating poxvirus is discussed.

Amino Acid Sequence↗
PubMed1985

Massive juvenile ossifying fibroma of maxillary sinus with orbital involvement.

A 14-year-old black girl had painless, progressive proptosis and upward displacement of the left eye for approximately six months. Computed tomography showed a massive tumour involving the maxillary sinus with extension into the sphenoid sinus, ethmoid sinus, and orbit. The mass was excised surgically and proved histopathologically to be a juvenile ossifying fibroma. The clinical and histopathological features of this uncommon orbital tumour are discussed and its place in the spectrum of fibro-osseous tumours of the orbital region is considered.

Adolescent↗
PubMed1991

Spontaneous hypoglycaemia due to a pleural fibroma: role of insulin like growth factors.

A 64 year old woman with a long history of "drop attacks" and dizzy spells was found to have spontaneous hypoglycaemia. A slowly enlarging pleural mass had been present for at least five years. At thoracotomy the mass (weight 1.7 kg) was excised and the hypoglycaemia ceased. Histologically the tumour was a pleural fibroma, with no features of malignancy. Endocrine tests before surgery showed a subnormal growth hormone response to spontaneous hypoglycaemia, a reduced concentration of serum insulin like growth factor I (IGF-I), and an inappropriately high concentration of serum insulin like growth factor II (IGF-II). After resection of the tumour the growth hormone response to insulin induced hypoglycaemia and the IGF-I and IGF-II concentrations were normal. These data suggest that the hypoglycaemia was due to production of IGF-II by the tumour, causing increased glucose utilisation and an impaired growth hormone counterregulatory response to hypoglycaemia.

Female↗
PubMed1977

Angiographic features of fibromas and fibrosarcomas.

Angiography was done in 38 cases of pathologically-confirmed fibrous-tissue tumor. All benign fibromatous tumors and one case of desmoid fibroma were angiographically normal. A great spectrum of angioarchitecture exists in fibrosarcomas, whether they are of bone or soft-tissue origin. Heterogeneous vascularity was seen in 55% of these cases, and was related to the cell composition of the tumor. There exists a close relationship between the number of vessels in a tumor and its degree of clinical and histopathological malignancy. The most vascular part of a tumor is the least differentiated and should be used for biopsies. Angiography can be used for the grading of fibrosarcomas, and probably for assessing clinical prognosis.

Adult↗
PubMed1979

Scintigraphic features of nonosteogenic fibroma.

Three cases of nonosteogenic fibroma or fibrous cortical defect are presented which demonstrated scintigraphic findings of minimal to mild increased uptake of bone-seeking radiopharmaceutical and thus helped to distinguish these lesions from other benign or malignant abnormalities. The authors suggest that the two types of lesion are not fundamentally different from one another.

Adolescent↗
PubMed1989

Desmoplastic fibroma of bone: radiographic analysis.

Desmoplastic fibroma (DF) of bone is a rare, nonmetastasizing but locally aggressive tumor that has been discussed infrequently in the radiology literature. The radiographs from 107 previously published cases of DF and seven cases from the authors' institution were analyzed to better understand and define its radiographic characteristics. DF was most common in the mandible, pelvis, and femur. A geographic pattern of bone destruction, with a narrow zone of transition and nonsclerotic margins, was seen in 80 (96%) patients with intraosseous DF for whom radiographs were available (83 patients). Internal pseudotrabeculation was seen in 76 (91%). Although widening of the host bone due to gradual apposition of periosteal new bone was common, occurring in 74 (89%) patients, distinct periosteal new bone occurred in only two (2%) patients with DF of intraosseous origin. The cortex was breached in 23 (28%) patients. Three cases of DF arising in the periosteum were identified and were differentiated radiographically from desmoid tumors of intraosseous or soft-tissue origin.

Adult↗
PubMedDate not supplied

Chondromyxoid fibroma of the upper thoracic spine in a 7-year-old patient. A case report and review of the literature.

BACKGROUND: We report a case of a 7-year-old white female who presented with acute, progressive bilateral lower extremity weakness over 48 h. METHODS: Case report and presentation of clinical, radiological and pathological data on a single case of chondromyxoid fibroma (CMF) of the T2 vertebral body. RESULTS: Magnetic resonance imaging of the thoracic spine revealed an extensive mass invading the lamina of the second thoracic vertebra, causing extensive cord compression and progressive neurological deterioration. Surgical resection and pathologic study of the mass revealed a CMF. CONCLUSIONS: A thorough Medline search has revealed that only 25 cases of spinal CMF have been reported, making this lesion an extremely rare bone tumor.

Child↗
PubMed1995

Pleomorphic fibroma on the scalp.

We present the eleventh case of benign pleomorphic fibroma arising on the scalp in a young Korean woman. Histopathologically these lesions were characterized by a polypoid or dome-shaped cutaneous fibrous mass with sparse cellularity but striking nuclear atypia and rare mitotic figures. They all showed benign clinical behavior, despite these histopathological findings.

Actins↗