Tumor overgrowth

The major complications of metallic stenting include hemorrhage, migration, tumor ingrowth, tumor overgrowth, severe pain, perforation, and fistula formation (Saxon et al. 1994). 

Recurrent dysphagia occurs in 10%-36% of patients and maybe due to stent migration, food bolus obstruction, or recurrent strictures due to tumor ingrowth, tumor overgrowth (Acunas et al. 1996 Cwikiel et al. 1998 Song et al. 1994 Laasch et al. 1998 Saxon et aL 1995 Morgan et al. 1996 Bartelsmann et al. 2000). 

Rarer complications of plastic tube stents include tracheobronchial ulceration with secondary hemorrhage, perforation of the tracheobronchial wall with secondary mediastinitis and septic shock, tumor overgrowth at the proximal or distal stent margin. 

Metalhc stents can induce granuloma formation, which might be excessive, particularly in benign strictures. A complication of uncovered stents is tumor growth through the open mesh. In addition, function of covered stents can be impaired by tumor overgrowth at the proximal and distal margins. 

In the Japanese multicenter trial of the uncovered Ultraflex stent (Miyazawa et al. 2000), tumor ingrowth (24%) and tumor overgrowth (21%) were the most frequent complications during the 2-month follow up period. Mucus retention was noted in 9% and granuloma formation was seen in 3%. No migrations of the uncovered stents occurred. 

Rat embryo fibroblasts after several days of growth on plates. Normally these cells stop growing as they approach confluency (top frame). Overgrowth of the monolayer by rounded cells is indicative of cellular transformation. Two transformed foci are seen in cells pretreated with both ras- and myc-containing DNA (bottom frame). The transformed cells produced similar transformed cells when repleated and when injected into whole animals produce tumors with a much higher frequency than normal cells. 

Waghome, C., Thomas, M., Lagarde, A., Kerbel, R. S. and Breitman, M. L. (1988). Genetic evidence for progressive selection and overgrowth of primary tumors by metastatic cell subpopulations. Cancer Res. 48, 6109-6114. 

There has been concern about the potential for proton pump inhibitors to cause enterochromaffin-hke cell hyperplasia, gastric carcinoid tumors and gastric cancers, colorectal polyps and adenocarcinoma, atrophic gastritis, and intestinal metaplasia in patients with H. pylori infection, and bacterial overgrowth. 

Biliary obstruction due to stone, tumor, or primary biliary cirrhosis Zollinger-Ellison syndrome (causes hyperacidity) bacterial overgrowth and stasis administration of drugs, neomycin, and cholestyramine Ileal disease or resection... 

The immunophenotype of this tumor closely parallels that of endometrial stromal neoplasms when stromal overgrowth is not present. The mesenchymal component of miillerian adenosarcomas without stromal overgrowth typically expresses ER, PR, androgen receptors, CD 10, and WTl, while significant minorities also express smooth muscle actin and even pan-cytokeratins (Fig. 18.19).2°F227-229 demonstrating stromal... 

Overall, studies aimed at developing better prognostic markers in phyllodes tumors have suffered from low sample size, a lack of patient follow-up data, and lack of reproducibility. The most significant consistently reported variables in the prediction of phyllodes tumor behavior remain histologic characteristics, in particular the presence of stromal overgrowth and adequate surgical resection margins. 773-279... 

Lu YJ, Birdsall S, Osin P, et al. Phyllodes tumors of the breast analyzed by comparative genomic hybridization and association of increased Iq copy number with stromal overgrowth and recurrence. Genes Chromosomes Cancer. 1997 20 275-281. 

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