Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Neoplastic Processes”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,297 records · Page 72Linked to original sources
PubMed2000

A search for chemical agents causing human cancer--lessons learned from rodent carcinogenicity studies.

Analysis of classical life-time rodent bioassays conducted over the past 20 years under conditions of Good Laboratory Practice Regulations has led to an improved understanding of possible factors involved in oncogenesis in humans. Improvements in study design coupled with more detailed pathological examinations have led to new insights whereby neoplastic processes can be more clearly identified and understood with confidence in animal models. Improvements in the ability to identify potential risks through continued animal testing combined with incorporation of advances in genetics and molecular biology in elucidating mechanistic factors will greatly facilitate future research efforts to identify causative agents of human cancer. A great deal of attention will have to be paid to the concept of threshold doses and exposure levels that may be required to achieve preneoplastic conditions or the induction of carcinogenic processes. Future concerns of hazards, risk assessment and the evaluation of carcinogenic potential will involve an amalgamation and understanding of radiological and biological events, especially those of carcinogenic microorganisms, the effects of food and air borne carcinogens, effects of pollution, exposure to xenobiotics and imbalances and disruption of normal biologic functioning of endogenous physiologically active substances, to achieve a better understanding and ultimate prevention of human cancer.

Animals↗
PubMed1997

Principles of antibiotic prescribing in the elderly.

Clinicians providing care to elderly patients must appreciate the subtle clinical manifestations that herald the onset of life-threatening infectious disease. Aged patients with an infection may have neither fever nor leucocytosis, making diagnosis challenging. Often, the early features of infectious disease are nonspecific and may resemble inflammatory or neoplastic processes, or there may be insufficient time to await definitive laboratory confirmation, and empirical antimicrobial treatment must be initiated. Aging involves inevitable deleterious alterations in biological processes and, in many elderly patients, this is most strongly characterised by diminished renal functional capacity. This has a major influence on antimicrobial prescribing in the elderly, because therapeutic efficacy must be achieved while minimising the risk of drug-related toxicity. Before prescribing an antibiotic to an aged patient with an infection, the clinician must be cognisant of the patient's drug allergy history and the other drugs that the patient is taking. Ignorance of potential drug-drug interactions can result in ineffective treatment or enhanced toxicity. The therapy of elderly patients with infections is being expanded. To reduce costs and enhance the efficiency of care, systems have been developed to provide antimicrobial care in the home and in long term care facilities. Home healthcare has burgeoned, and drugs that are well tolerated, have a broad spectrum of activity and are simple to administer (e.g. ceftriaxone and fluoroquinolones) appear to be eminently suitable for this therapeutic role. Physicians must also be informed of the factors responsible for the emergence of resistant bacteria that are contributing to infections in institutional and community settings. Clinicians should strive to curb inappropriate antibiotic use to stem the tide of infections that are caused by multidrug-resistant bacteria.

Aged↗
PubMed1977

Infiltrating neoplasms of the kidney.

Some neoplastic processes which involve the kidney develop not as a distinct localized mass, but rather as an infiltrating process which replaces the renal parenchyma, causes little or no mass effect, and contains little if any neovascularity. These neoplasms include (1) carcinoma of the renal pelvis when it invades the parenchyma (transitional cell and squamous cell); (2) blood-borne metastatic squamous cell carcinoma to the kidney (most frequently from the lung): (3) renal lymphoma of the infiltrating variety; and (4) infiltrating sarcomatous type of hypernephroma. While the urographic and angiographic appearance of these infiltrating lesions can be similar, clinical aspects are usually sufficient to differentiate them. Radiographic findings include amputation of portions of the collecting system on urography and encasement of vessels with a loss of nephrogram on angiography.

Adenocarcinoma↗
PubMed1989

Contrast enhancement in spinal MR imaging.

We evaluated 44 patients with suspected spinal tumors or previous laminectomies with gadolinium-DTPA MR imaging in order to characterize the enhancement in normal, postoperative, and neoplastic intraspinal tissue. Using the signal intensity of CSF as an internal control, we calculated the percentage increase in signal intensity from pre- to postgadolinium studies. Tumors (astrocytoma, ependymoma, schwannoma) enhanced 70-350%; epidural scar, normal epidural venous plexus, and dorsal root ganglion enhanced up to 200%. Contrast enhancement does not per se distinguish neoplastic from normal tissue. Enhancement with gadolinium-DTPA appeared to increase the conspicuousness of intramedullary tumors but not intraosseous metastases. We believe that gadolinium-enhanced MR imaging is a valuable adjunct to routine MR imaging in the evaluation of intraspinal neoplastic processes and may be useful in delineating normal and postoperative structures in the spinal canal.

Contrast Media↗
PubMed1995

Renal osteodystrophy: imaging findings that mimic those of other diseases.

Musculoskeletal complications in patients with chronic renal failure are common and may be related to the disease itself or to treatment. The altered metabolism in patients with chronic renal failure leads to renal osteodystrophy, which consists of osteomalacia and secondary hyperparathyroidism [1]. Erosive changes attributable to secondary hyperparathyroidism may be easily confused with rheumatoid arthritis, seronegative spondyloarthropathies, infection, or even malignancy. Brown tumors and amyloid deposition can easily be mistaken for a neoplastic process. The purpose of this article is to illustrate radiographic findings that are caused by renal failure and that often mimic other diseases by use of plain radiographs, CT scans, and MR images. Particular emphasis is placed on periarticular findings.

Arthritis, Rheumatoid↗
PubMed1997

MR imaging of tophaceous gout.

OBJECTIVE: MR imaging is not routinely used for evaluation of tophaceous gout. However, gout may present clinically in an atypical, unusual, or confusing manner. A gouty tophus occasionally mimics an infectious or neoplastic process, and MR imaging may be obtained under these circumstances. The purpose of this study was to determine the MR imaging characteristics of intraosseous and soft-tissue tophi. MATERIALS AND METHODS: We identified 13 MR imaging examinations performed during a 27-month period on nine patients with gouty arthritis. All were men 42-70 years old. T1-, proton density-, and T2-weighted spin-echo MR images were obtained for all the examinations. Nine examinations included contrast-enhanced MR images. The findings were then evaluated, as were the corresponding radiographs. RESULTS: Five patients presented with articular involvement, three patients with an isolated soft-tissue mass, and one patient with persistent soft-tissue swelling. The duration of symptoms ranged from 3 months to more than 20 years. Nearly all the tophi were of intermediate signal intensity on T1-weighted images. On T2-weighted images, three sites revealed an overall increase in the signal intensity of the tophi, whereas 10 studies showed a heterogeneous decrease in signal intensity. All but one tophus showed homogeneous enhancement. Erosion of adjacent bone, synovial pannus, joint effusion, soft-tissue edema, and bone marrow edema were common associated findings. CONCLUSION: The MR appearance of tophi in patients with tophaceous gout is constant on T1- but quite variable on T2-weighted images. This variability in signal intensity could be related to calcium within a tophus. Tophaceous gout should be considered in the differential diagnosis when a mass reveals heterogeneously low to intermediate signal intensity, particularly if the adjacent bone shows typical erosive changes or if other joints are involved. When faced with this situation, radiologists may find it helpful to obtain a further clinical history and recommend evaluating the patient's serum urate level.

Adult↗
PubMed2000

CT of patients with right-sided colon cancer and distal ileal thickening.

OBJECTIVE: The purpose of this study was to analyze the incidence and primary causes of distal ileal wall thickening in 131 patients with right-sided colon cancer. SUBJECTS AND METHODS: During a 2-year period, 131 patients underwent surgical resection for right-sided colon cancer. Of these patients, we analyzed 13 who had distal ileal wall thickening on CT before surgery and also had the cause determined at pathology. CT findings were analyzed with regard to the morphologic features of colonic tumors, bowel wall involvement patterns of the distal ileum, and changes in the pericolic space. RESULTS: Distal ileal wall thickening occurred in 13 (10%) of the 131 patients who had right-sided colon cancer. Three patients had polypoid colon cancer, whereas the other 10 had infiltrative colon cancer. The mean thickness of the involved colonic segments was 1.6 cm (range, 1.0-2.2 cm) with a mean length of 5.2 cm (range, 2.5-10.0 cm). Pericolic infiltration was mild in six patients and moderate in four patients. The mean length and thickness of the affected ileal segments were 3.2 cm (range, 1.5-6.0 cm) and 1.1 cm (range, 0.7-2.0 cm), respectively. On histopathologic examination, neoplastic processes involved the distal ileum in nine (69%) of the 13 patients. This involvement was caused by either direct tumor invasion in seven patients or lymphatic spread in two. In four patients (31%), nonneoplastic processes with edema and congestion involved the distal ileum. CONCLUSION: The distal ileum may be abnormally thickened in about 10% of patients with right-sided colon cancer; this thickening results from tumor extension (69%) or a nontumorous process (31%).

Adult↗
PubMed1997

Epithelial hyperplasia of the extra-glandular excretory ducts of human minor salivary glands: a histopathologic study.

The histologic features of normal and hyperplastic epithelia of the extra-glandular excretory ducts of human minor salivary glands were studied, and their pathologic significance evaluated. Normal duct epithelium consisted of two layers: inner columnar cells, and basal cubical or squamous cells. A few goblet cells were present among the inner cells. Hyperplasia of the duct epithelia occurred focally or entirely, and was classified into the following histologic types: (1) simple hyperplasia, and (2) metaplastic hyperplasia, which were divided into (a) mucous cell hyperplasia, (b) oncocytic hyperplasia and (c) squamous cell hyperplasia. Squamous cell hyperplasia was subdivided into (i) acanthotic type and (ii) reserve cell-like type with or without dysplasia. Simple or metaplastic epithelial hyperplasia of the extra-glandular excretory ducts of minor salivary glands may be induced by chronic inflammation or other types of irritation, and proliferating cells of such regenerating tissue sometimes exhibit features reminiscent of a neoplastic process. Furthermore, it is suggested that metaplastic epithelial hyperplasia of the excretory minor salivary gland ducts could be the site of origin of tumor development, i.e., some oral squamous cell carcinomas may arise from primary lesions in the hyperplastic epithelium of the extraglandular excretory minor salivary gland ducts.

Carcinoma, Squamous Cell↗
PubMed1993

Inflammatory carcinoma masquerading as erythema annulare centrifugum.

A case of inflammatory carcinoma, or carcinoma erysipelatodes, clinically resembling erythema annulare centrifugum is reported. The cutaneous inflammatory carcinoma was due to metastasis by a signet-ring cell adenocarcinoma, probably of gastrointestinal origin. This is the third reported case of inflammatory carcinoma with signet-ring cell infiltration. Cancer patients with atypical or unusual inflammatory dermatoses should be evaluated by skin biopsy because of the possible association with the internal neoplastic process.

Adenocarcinoma, Mucinous↗
PubMed2002

Motor denervation of tumors of the head and neck: changes in MR appearance.

PURPOSE: We reviewed the MR appearance of motor denervation of the third (mandibular) division of the trigeminal nerve (V3) and of the hypoglossal nerve. METHOD: Six cases of tumor of the head and neck with motor denervation were retrospectively evaluated. These comprised two patients with V3 denervation, three patients with hypoglossal nerve denervation, and one patient with both V3 and hypoglossal denervation. The observation was conducted for 6 to 44 months after onset. In denervated muscles, changes in signal intensity in T(1)- and T(2)-weighted images, degree of contrast enhancement, and volume of muscle were estimated during the follow-up period. RESULTS: In all cases of V3 denervation, the muscles showed no change in signal intensity in the T(1)-weighted images up to three months after onset. In two cases of hypoglossal denervation, the tongues appeared ipsilaterally hyperintense in the T(1)-weighted images within the first three months. In one case with V3 denervation and two cases with hypoglossal denervation, denervated muscles appeared hyperintense in the T(2)-weighted images up to three months after onset. At three months after denervation, the signal intensities of all motor-denervated areas increased in both T(1)- and T(2)-weighted images. Postcontrast T(1)-weighted images obtained within the first three months displayed contrast enhancement of all denervated muscles. In three cases of V3 denervation, the volumes of the affected muscles were reduced after the first three months. In three cases of hypoglossal denervation, the ipsilateral volume of the tongue decreased at three months after onset. CONCLUSION: Up to three months after onset, the denervated muscles appeared hyperintense in the T(2)-weighted images and contrast enhancement in postcontrast T(1)-weighted images before fatty infiltration and volume loss were apparent. Familiarity with the MR appearance of denervated muscles accompanying tumors of the head and neck is important to avoid confusion with inflammatory or neoplastic processes.

Adult↗
PubMedDate not supplied

Molecular pathogenesis of transplacentally induced mouse lung tumors.

Previous studies from this and other laboratories have shown that treatment of pregnant mice with 3-methylcholanthrene (MC) caused lung tumors in the offspring, the incidence of which correlated with fetal inducibility of Cyp1a1. Analysis of paraffin-embedded lung tissue for Ki-ras-2 mutations indicated that 79% of the lesions examined contained point mutations in codons 12 and 13 of the Ki-ras-2 gene locus, the majority of which (84%) were G-->T transversions. The mutational spectrum was dependent on the tumor stage, as both the incidence of mutation and type of mutation produced correlated with malignant progression of the tumor. Mutations occurred in 60% of the hyperplasias, 80% of the adenomas, and 100% of the adenocarcinomas. In the tumors with mutations, GLY12-->CYS12 transversions occurred in 100% of the hyperplasias, 42% of the adenomas, and 14% of the adenocarcinomas. GLY12-->VAL12 transversions were not observed in hyperplasias and occurred in 42% of the adenomas and 57% of the adenocarcinomas. The remaining ASP12 and ARG13 mutations occurred only in adenomas (17%) and adenocarcinomas (29%). The tumors were also analyzed for alterations in the structure or function of the tumor suppressor genes Rb, p53, and Cdkn2a. No mutations were observed in exons 5-8 of the p53 gene. SSCP analysis demonstrated that 2 of 15 lung tumors contained shifted bands at the Cdkn2a gene locus. Sequence analysis had identified these as mutations in exon 2, with a CAC-->TAC transition at base 301 (HIS74-->TYR74) in tumor 23-1 and GGG-->GAG transition at base 350 (GLY90-->GLU90) in tumor 36-1. Northern blot analysis of the larger tumors revealed that 14 of 14 of these large lung tumors exhibited markedly decreased expression of Rb gene transcripts. These results were confirmed by immunohistochemistry. The larger tumors, which exhibited features of adenocarcinomas, showed a marked reduction or almost complete absence of nuclear pRb staining compared with smaller adenomas and normal lung tissue. The results suggest that Ki-ras-2 mutations are an early and frequent event in lung tumorigenesis, and that the type of mutation produced by environmental chemicals can influence the carcinogenic potential of the tumor. The results obtained with the Cdkn2a and Rb genes suggest that alterations in the Rb regulatory axis may play a key role in the pathogenesis of the pulmonary tumors and appear to occur later in the neoplastic process. It appears from these experiments that the combination of mutated Ki-ras-2 and alterations in the Rb regulatory gene locus, which are frequent alterations in human lung tumors, may be the preferred pathway for lung tumor pathogenesis in mice exposed transplacentally to environmental carcinogens.

Adenocarcinoma↗
PubMedDate not supplied

Comparative ultrastructure of soft-tissue myxoid tumors.

This comparative analysis of the characteristic ultrastructural features specific for intramuscular myxoma, myxoid liposarcoma, extraskeletal myxoid chondrosarcoma, myxoid malignant fibrous histiocytoma, myxoid variant of dermatofibrosarcoma protuberans, and myxoid neurilemmoma is based on our own studies of 52 cases. In spite of the histologic resemblance frequently observed, these tumors can be easily distinguished on the basis of cytoplasmic and extracellular features by electron microscopy. The value of electron microscopy in the diagnosis of myxoid tumors of soft tissues lies mainly in its potential to provide additional information concerning the cell types involved in the neoplastic process and their line of differentiation.

Chondrosarcoma↗
PubMedDate not supplied

Multinucleated giant stromal tumor of the omentum: report of a case with immunohistochemical and ultrastructural investigation.

Multinucleated giant stromal cells (MGSC) have been described in a variety of lesions of various anatomical sites. They are generally believed to be derived from fibroblasts or myofibroblasts. Their size and bizarre appearance may lead to an erroneous interpretation of infiltrating malignant cells, but they are regarded as reactive in nature. MGSC also seem to participate in a neoplastic process and form a part of tumors called giant cell fibroblastomas (GCF). In GCF, multinucleated giant cells are sparsely scattered throughout the tumor, which is composed of loosely arranged spindle cells. Thus far, no tumor composed of MGSC entirely, to the best of the authors' knowledge, has been reported. This study involved an 80-year-old female with an omental tumor, which is believed to represent the first case of tumor of MGSC. The patient developed abdominal pain; a large abdominal tumor measuring 18 x 15 x 5 cm by computerized tomography was found located between the left lobe of the liver, the transverse colon, and the greater curvature of the stomach. Although the tumor was adherent to the above organs and infiltrating the omentum, it was resectable. Grossly, the tumor was highly vascular and the surface was shaggy with no recognizable capsule. The cut surfaces were red to tan with frequent cystic spaces containing bloody material. Microscopically, the tumor cells were large and multinucleated (2-6 nuclei) with prominent nucleoli. The cytoplasm was abundant and stained amphophilic. These tumor cells formed moderately cellular sheets filling the spaces between the varying sized vessels. There was prominent vascularity throughout the tumor. DNA study by image analysis revealed aneuploidy peaks. On immunohistochemistry, the tumor cells were strongly positive for vimentin, moderately positive for actin along the periphery of the cytoplasm, and negative for cytokeratin, EMA, myoglobin, S-100, CEA, Factor XIIIa, HMB-45, and HAM56 and KP-1. Ultrastructurally, the cytoplasm contained rich profiles of RER with scattered lysosomes. The cell borders were slightly irregular with occasional subplasmalemmal densities facing loosely arranged collagenous stroma. The light microscopic, immunohistochemical, and electron microscopic features of tumor cells were remarkably similar to MGSC. The tumor size and gross appearance suggested a malignancy, but it was a diploid tumor and the patient remains disease free 5 years after a complete resection.

Aged↗
PubMed1989

Oncologic causes of precocious puberty.

Tumors are rare, but well-documented causes of precocious puberty in both sexes. The therapeutic and prognostic implications of a diagnosis of cancer require that the presence of a neoplastic process be ruled out in any case of precocious puberty. Granulosa-cell tumor of the ovary and Leydig-cell tumor of the testis are the most frequent gonadal tumors inducing precocious pseudopuberty in the two sexes. Adrenal tumors sustain a variety of endocrine syndromes, the most frequent one being virilization with or without hypercortisolism. Pure feminizing adrenal neoplasms have been described. For reasons not yet well understood, hypothalamochiasmatic glioma (beta-HCG) secreting tumors have almost never been described in association with female precocious puberty. Among these neoplasia, pineal germ-cell tumor inducing sexual maturation must be included. Hypothalamochiasmatic glioma and craniopharyngioma are the two cerebral tumors capable of inducing true precocious puberty. Even if equally distributed between both sexes, these tumors interfere with sexual maturation less frequently in girls than in boys. Hypothalamic hamartoma is considered a benign tumor, since it does represent a space-occupying mass. It more correctly could be called a malformation if its histologic characteristics are recalled. This cerebral lesion is now frequently described in children with true precocious puberty, probably because of improved diagnostic imaging methods.

Child↗
PubMed1993

Functional differences of T cells in B-chronic lymphocytic leukemia.

B cell chronic lymphocytic leukemia (B-CLL) is a disease characterized by an accumulation of monoclonal lymphocytes of B cell origin. Although the neoplastic process involves the B lymphocyte compartment, phenotypic and functional defects within the T lymphocyte population implicate their possible role in the pathogenesis of the disease. We analyzed the functional and morphological integrity of T lymphocytes from the peripheral blood of 64 patients with B-CLL. The activation of B-CLL T cells after PHA stimulation was determined by measuring [3H]-thymidine incorporation, assessing cell numbers in parallel cultures, and by monitoring the lymphocyte subsets during 9 days of cultivation. Our results indicate the presence of three functionally different populations of T cells in the peripheral blood of B-CLL patients. We present evidence for an increased proliferative potential of T lymphocytes from a group of patients with B-CLL.

Aged↗
PubMed1997

Biomarkers--the new frontier in the pathology of invasive and preinvasive neoplasias.

The papers in this symposium were presented at the 1996 Annual Meeting of the Biological Stain Commission. The authors hope that the discussion of biomarkers in the papers included in this issue and the literature reviewed in them will be useful to diagnostic pathologists as well as to investigators studying neoplastic processes in general.

Biomarkers↗
PubMed2006

Imaging of primary central nervous system lymphoma.

Primary central nervous system lymphoma (PCNSL) is an aggressive neoplastic process that occurs in both immunocompetent and immunocompromised patients. Over the past 30 years there has been a steady increase in the number of cases in both patient populations. The imaging features for the disease and demographic characteristics within these patient populations vary, and in this article the authors describe the salient features of these two groups.

Brain Neoplasms↗
PubMed1998

Spinal dural enhancement on magnetic resonance imaging associated with spontaneous intracranial hypotension. Report of three cases and review of the literature.

This report offers a description of typical changes seen on gadolinium-enhanced magnetic resonance (MR) imaging of the entire spine that indicate spontaneous intracranial hypotension (SIH). To the authors' knowledge, this is the first report of its kind. They describe three cases of SIH that were accompanied by dural enhancement throughout the neuraxis on imaging, with the evolution of associated subdural and epidural fluid collections in the spine. Recognition of this disorder is important to be able to distinguish it from an infectious or neoplastic process in which surgical intervention might be warranted. Evaluation using gadolinium-enhanced cranial and spinal MR imaging in patients with postural headaches and an (111)In-labeled cerebrospinal fluid leak study are discussed. Treatment with an epidural blood patch is shown to be particularly effective, with resolution of the radiological and clinical findings.

Adult↗