RESUMO
OBJECTIVE: Low-grade mucinous tumors of the appendix appear to have a simple histological structure. Paradoxically, reports have suggested a greater frequency of Ki-ras gene mutation in these lesions than in more complex lesions such as benign colonic adenomas and carcinomas. We assessed several molecular genetic changes, including Ki-ras gene mutations, in a large series of low-grade mucinous tumors of the appendix. MATERIAL AND METHODS: We retrospectively ascertained low-grade mucinous tumors of the appendix from computerized pathology records. Extracted DNA was analyzed for APC and DCC gene loss of heterozygosity, microsatellite instability and for the presence of Ki-ras gene mutation using standard molecular techniques. Controls consisted of normal appendices, other appendiceal neoplasms, and ovarian mucinous cystadenomas. RESULTS: A total of 31 low-grade appendiceal mucinous tumors were identified. All were microsatellite stable and none demonstrated loss of heterozygosity for the APC or DCC genes. By contrast, all 31 lesions contained a Ki-ras gene mutation. CONCLUSIONS: The presence of a Ki-ras gene mutation in all lesions, with no other molecular changes identified, strongly suggests a possible etiological role of the Ki-ras mutation in the development of this particular lesion of the appendix. Based on other work regarding intestinal bacteria, we hypothesize a relationship between chronic inflammation of the appendix from bacterial overgrowth and Ki-ras gene mutation.
Assuntos
Neoplasias do Apêndice/genética , Cistadenoma Mucinoso/genética , Genes ras/genética , Neoplasias Ovarianas/genética , Adenocarcinoma/genética , Adenoma Viloso/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias do Apêndice/patologia , Tumor Carcinoide/genética , Cistadenoma Mucinoso/patologia , Análise Mutacional de DNA , DNA de Neoplasias , Feminino , Genes APC , Genes DCC/genética , Humanos , Pólipos Intestinais/genética , Perda de Heterozigosidade/genética , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Estudos Retrospectivos , Adulto JovemRESUMO
Littoral cell angioma is an uncommon primary vascular neoplasm of the spleen. It frequently follows a benign course, but cases with aggressive behavior have been described. We present a case of this rare disease highlighting radiological examinations showing a rapid increase in the size of the spleen as well as an increase in the number and size of existing nodules. We also discuss the relationship of this disorder to chronic infections and its possible association with Epstein Barr virus.
RESUMO
PURPOSE: Preoperative chemotherapy and radiation has become the standard of care for many patients with rectal cancer. The therapy may have toxicity and delays definitive surgery. It would therefore be desirable to identify those cancers that will not regress with preoperative therapy. We assessed a series of rectal cancers for the molecular changes of loss of heterozygosity of the APC and DCC genes, K-ras mutations, and microsatellite instability, changes that have clearly been associated with rectal carcinogenesis. METHODS AND MATERIALS: Diagnostic colonoscopic biopsies from 53 patients who received preoperative chemotherapy and radiation were assayed using polymerase chain reaction techniques followed by single-stranded conformation polymorphism and DNA sequencing. Regression of the primary tumor was evaluated using the surgically removed specimen. RESULTS: Twenty-three lesions (45%) were found to have a high degree of regression. None of the molecular changes were useful as indicators of regression. CONCLUSIONS: Recognized molecular changes critical for rectal carcinogenesis including APC and DCC loss of heterozygosity, K-ras mutations, and microsatellite instability are not useful as indicators of tumor regression following chemoradiation for rectal carcinoma.
