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Query: UMLS:C0001430 (adenoma)
 21,222 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous research suggests that iron acts as a prooxidant to increase the risk of colorectal neoplasia. This study examined effects of dietary intake of iron on colorectal adenoma recurrence using data from an antioxidant clinical trial. All subjects were free of polyps at study entry but had at least one adenoma removed within the 3 months before enrollment. Follow-up colonoscopies were conducted after 1 and 4 years. Patients who developed one or more adenomatous polyps between years 1 and 4 were classified as cases; all others were controls. Dietary iron intake at baseline and at the end of the study was estimated from self-administered food frequency questionnaires and averaged together for each subject, energy-adjusted, and categorized into quartiles. Odds ratios were adjusted for age, center, sex, calories, treatment group, and alcohol, fiber, folate, and fat intakes in unconditional logistic regression analysis. Dietary iron was inversely associated with adenoma risk, although risk did not decrease monotonically with increasing intake. Odds ratios comparing second, third, and fourth quartiles to the lowest quartile were 0.61 [95% confidence interval (CI), 0.37-1.02], 0.80 (95% CI, 0.45-1.44), and 0.37 (95% CI, 0.19-0.73), respectively. A limited examination showed no clear evidence that use of iron supplements affected risk of recurrence in this study population. This study provides evidence against the hypothesis that recent dietary intake of iron increases risk for colorectal adenomas. However, these results may reflect the presence of other dietary factors found in combination with iron.
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PMID:Dietary iron and recurrence of colorectal adenomas. 941 98

High concentrations of iron in the diet have been shown to increase chemically induced colorectal tumors in rats. It is therefore important to understand the influence of dietary iron on the concentration of unabsorbed iron in the large intestine and its distribution between soluble and insoluble pools in the luminal compartment. We sought to investigate this issue and to establish whether iron modifies mucosal cell proliferation, which is thought to influence initiation and progression through the adenoma carcinoma sequence. In the first experiment, four groups of seven rats were fed diets at two concentrations of iron, 29 and 102 mg/kg, with or without the addition of 2.5 g phytic acid/kg. The concentrations of iron in the contents of the large bowel extractable with water ("free iron") or a buffered EDTA solution ("exchangeable iron") were determined. The concentration of freely soluble iron increased approximately 100% with iron supplementation in both the cecum and the colon, and there was an approximately five- to sixfold increase in exchangeable iron at both sites (P < 0. 05). In a second experiment with identical feeding conditions, there was a significantly greater number of cell divisions per crypt in the colon of the high iron group and a significantly greater number of cell divisions in the upper part of the crypt in the cecum. The concentrations of free and exchangeable iron observed in colonic contents in this study are consistent with those reported by others to increase free radical production in fecal material. Further studies are required to determine whether the small changes in crypt cytokinetics are a consequence of oxidative mucosal damage.
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PMID:Increases in the concentrations of available iron in response to dietary iron supplementation are associated with changes in crypt cell proliferation in rat large intestine. 944 39

Two cases are presented in which the MRI findings following superparamagnetic iron oxide (SPIO) enhancement of hepatic adenoma and focal nodular hyperplasia (FNH) are described. Benign liver lesions show uptake of iron oxide particles, which allows differentiation from malignant liver lesions and tumors of other cell origin. There have been several publications in the literature, but the SPIO-enhanced MR findings of hemorrhage in a hepatic adenoma have not been previously described. To illustrate the role of SPIO-enhanced MRI in the differential diagnosis of adenoma from FNH, the SPIO-enhanced MR features of FNH are presented.
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PMID:Hepatic adenoma and focal nodular hyperplasia: MR findings with superparamagnetic iron oxide-enhanced MRI. 955 34

The purpose of this study was to compare small and ultrasmall superparamagnetic iron oxide particles (SPIO and USPIO, respectively) as MR contrast agents for the evaluation of focal hepatic disease. In two different patient groups (SPIO [n = 53], USPIO [n = 27]), with focal liver disease (metastases, hepatocellular carcinoma [HCC], hepatocellular adenoma [HCA], and focal nodular hyperplasia [FNH]), spin-echo T1- and T2-weighted images (T1WI, T2WI) were obtained at 1.0T, before and after intravenous contrast administration. The percentage signal-to-noise ratio (SNR) change and lesion-to-liver contrast (LLC) were measured and statistically compared. The liver decreased in signal intensity (SI) after SPIO administration (-28%) and increased after USPIO administration (+16%) on T1WI. On T2WI, the liver decreased in SI on postcontrast images with both agents (-78% SPIO, -73% USPIO). This difference was not statistically significantly different (P < or = .07). Both SPIO and USPIO provided >500% improvement in LLC on T2WI. On T1WI, LLC was increased in metastases (120%) and HCC (325%) with SPIO. Post-USPIO, LLC was increased on T1WI only in metastases (>500%). Both SPIO and USPIO show excellent hepatic uptake, presumed secondary to reticuloendothelial activity, based on the degree of %SI change seen in the liver after administration of contrast on T2WI. However, USPIO preparations exhibit blood pool activity that may aid in further characterization of focal liver lesions, as is evidenced by their greater T1 effect in the liver and in some focal liver lesions.
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PMID:MRI in focal liver disease: a comparison of small and ultra-small superparamagnetic iron oxide as hepatic contrast agents. 978 44

The purpose of this study was to evaluate the potential of superparamagnetic iron oxide particles (SPIO) as tissue specific contrast agent in magnetic resonance (MR) imaging in detection and characterization of focal hepatic lesions. We investigated 45 patients with focal hepatic lesions. T1-weighted SE (TR 650/TE 15 ms) and T2-weighted SE (TR 2015-2030/TE 45 and 90 ms) unenhanced images were obtained. After SPIO application we performed T1-weighted images with and T2-weighted images with and without fat suppression using the same image parameters. Liver signal intensity decreased by 74% (min 47%, max 83%) on T2-weighted images after application of the contrast agent. Benign lesions (FNH, adenoma) showed an average signal drop of 40% (min 20%, max 47%) whereas malignant lesions showed no significant change of signal intensity on post-contrast images. The mean tumor-to-liver contrast-to-noise ratio (C/N) was improved in all post-contrast sequences irrespective of the lesion type. An additional increase of tumor-to-liver contrast by use of fat suppression technique could be established in the slightly T2-weighted sequence (TE 45 ms). In metastases, divided in different size groups, we could determine a significant size relation of tumor-to-liver C/N. After SPIO application the number of detected lesions increased distinctly, especially small foci are more easily demonstrated. SPIO particles are a efficacious contrast agent for MR examinations of the liver. For tumor characterization T1- and T2-weighted pre- and post-contrast images are necessary. The T1-weighted sequences are helpful to differentiate benign lesions such as cysts and hemangiomas from malignant lesions. Detection and differential diagnoses of hepatic lesions are improved by use of the SPIO-particles.
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PMID:MRI with superparamagnetic iron oxide: efficacy in the detection and characterization of focal hepatic lesions. 1019 81

Adenocarcinoma arising at an ileostomy is uncommon, and only 29 cases have been reported in the literature. The case of a 54-year-old man who developed an adenocarcinoma at a Brooke ileostomy is reported. The ileostomy had been fashioned 21 years earlier after proctocolectomy for familial adenomatous polyposis (FAP). A wide local excision of the stoma was performed, and a new Brooke ileostomy was fashioned on the opposite side of the abdomen. Histopathologic examination revealed a well-differentiated adenocarcinoma with early invasion of the submucosa. On hematoxylin and eosin staining, the ileal mucosa adjacent to the tumor showed signs of colonic metaplasia, including loss of villous architecture and a reduced number of Paneth cells. Mucin staining using the high iron diamine-alcian blue stain demonstrated a mixture of sulfomucin and sialomucin in the ileal mucosa near the tumor, confirming colonic metaplasia. Ileostomy site carcinogenesis can be attributed to both the colonic metaplasia and the inherent nature of FAP or ulcerative colitis (UC), where colonic mucosa is susceptible to adenoma formation or dysplasia. Longstanding ileostomies in patients with FAP or UC should be followed to exclude the development of adenoma, dysplasia, or cancer.
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PMID:Familial adenomatous polyposis: a case report and histologic mucin study. 1037 42

Minimal deviation adenocarcinoma (MDA), or adenoma malignum, of the uterine cervix is a diagnostically problematic disease because of the difficulty in differentiating it histologically from normal cervical glands. To evaluate the use of mucin phenotyping for differentiating MDA from other conditions, we performed alcian blue pH 2.5/periodic acid-Schiff (AB-PAS) staining and high iron diamine (HID)-AB staining on routinely processed sections of 11 MDAs, 20 unremarkable cervical glands, 9 cervical glandular hyperplasias occurring in association with mucinous ovarian tumors, and 41 conventional cervical adenocarcinomas. In all 11 MDAs and 11 conventional cervical adenocarcinomas, the tumor cell cytoplasm was stained diffusely red by PAS, indicating that MDA cells produce neutral mucin almost exclusively. The amount of acid mucins, both sulfomucin and sialomucin, was decreased markedly by HID-AB. For four MDAs, preoperative biopsy specimens also showed diffuse cytoplasmic neutral mucin. In contrast, the cytoplasm of constituent cells was stained purple to violet by AB-PAS in all unremarkable cervical glands and glandular hyperplasias, indicating that both acid and neutral mucins were produced in equal amounts, sulfomucin being stained predominantly by HID-AB. Of the 30 conventional cervical adenocarcinomas, 28 showed both acid and neutral mucins and two showed acid mucin only in goblet cells, or in part of the cytoplasm or cell surface of constituent cells, where acid mucin consisted predominantly of sulfomucin in 14 and sialomucin in 16. AB-PAS and HID-AB are simple and orthodox histochemical methods which are effective for differential diagnosis of MDA and can contribute to its early detection and treatment.
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PMID:Reappraisal of orthodox histochemistry for the diagnosis of minimal deviation adenocarcinoma of the cervix. 1075 3

Both body iron stores and dietary iron intake have been reported to increase risk of colorectal neoplasms. We assessed whether serum ferritin concentration was associated with recurrence of colorectal adenomas among 733 individuals with baseline determinations of ferritin as part of a multicenter clinical trial of antioxidant supplements for adenoma prevention. All study participants had at least one adenoma removed within 3 months before enrollment, and 269 of them developed one or more adenomas between follow-up colonoscopies conducted 1 and 4 years after enrollment. Baseline serum ferritin concentrations were analyzed both as a log-transformed continuous variable and as a categorical variable, defined as whether iron stores were nonreplete and low (ferritin < or =30 microg/liter), nonreplete and borderline (31-70 microg/liter), replete and adequate (71-160 microg/liter), or replete and high (>160 microg/liter). Analyses were based on multiple logistic regression models, including age, sex, study center, energy, alcohol, fiber, folate, and total fat intake, number of months between colonoscopic examinations, smoking status, and aspirin use. Overall, there was no statistically significant linear association between log ferritin concentration and adenoma recurrence (P = 0.33). Risk of adenoma recurrence was modestly increased among participants with ferritin concentrations >70 microg/liter relative to those with lower ferritin (odds ratio, 1.39; 95% confidence interval, 0.96-2.02). This result seemed more pronounced among women than men. Dietary intake of iron and red meat was inversely associated with adenoma recurrence among participants with replete iron stores but not consistently associated among those with nonreplete stores. Our findings suggest that any role of iron stores and dietary iron in influencing risk of colorectal adenoma recurrence is likely complex.
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PMID:Serum ferritin concentration and recurrence of colorectal adenoma. 1086 99

A 22-year-old woman with a "hot" thyroid nodule who was being treated with minocycline for severe acne vulgaris is presented. A partial thyroidectomy specimen revealed a black adenoma. Microscopically, the black pigment was found in the follicular cells and the colloid of the adenoma. The pigment was bleached with potassium permanganate and was Fontana-Masson stain positive. It was negative for iron, periodic acid-Schiff, and acid-fast Ziehl-Neelsen stains. All these feature suggest a melanin-like pigment. However, electron microscopic examination revealed a dense osmophilic material present within the lysosomes of the follicular cells. No melanosomes were present. Twenty-six previously reported cases are reviewed, and the possible mechanisms for the deposition of the pigment in the adenoma and its relation to minocycline degradation products are discussed.
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PMID:Black thyroid adenoma. Clinical, histochemical, and ultrastructural features. 1093 53

Magnetic resonance imaging (MRI) relies on the physical properties of unpaired protons in tissues to generate images. Unpaired protons behave like tiny bar magnets and will align themselves in a magnetic field. Radiofrequency pulses will excite these aligned protons to higher energy states. As they return to their original state, they will release this energy as radio waves. The frequency of the radio waves depends on the local magnetic field and by varying this over a subject, it is possible to build the images we are familiar with. In general, MRI has not been sufficiently sensitive or specific in the assessment of diffuse liver disease for clinical use. However, because of the specific characteristics of fat and iron, it may be useful in the assessment of hepatic steatosis and iron overload. Magnetic resonance imaging is useful in the assessment of focal liver disease, particularly in conjunction with contrast agents. Haemangiomas have a characteristic bright appearance on T2 weighted images because of the slow flowing blood in dilated sinusoids. Focal nodular hyperplasia (FNH) has a homogenous appearance, and enhances early in the arterial phase after gadolinium injection, while the central scar typically enhances late. Hepatic adenomas have a more heterogenous appearance and also enhance in the arterial phase, but less briskly than FNH. Hepatocellular carcinoma is similar to an adenoma, but typically occurs in a cirrhotic liver and has earlier washout of contrast. The appearance of metastases depends on the underlying primary malignancy. Overall, MRI appears more sensitive and specific than computed tomography with contrast for the detection and evaluation of malignant lesions.
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PMID:Magnetic resonance imaging (MRI) and diseases of the liver and biliary tract. Part 1. Basic principles, MRI in the assessment of diffuse and focal hepatic disease. 1105 26


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