Dietary Fibers And Colon Cancer*
Herman Autrup, Gary M. Williams in Experimental Colon Carcinogenesis, 2019
Dimethylhydrazine or its derivatives can produce tumors at any site within the intestine of the experimental animal.47 However, in the small intestine, the vast majority are found near the major bile duct providing additional evidence that either bile or some component excreted in bile or pancreatic juice is important. Tumors occur uncommonly in jejunum, and rarely, if ever, develop in the ileum. Almost all small intestinal tumors are epithelial in type. Moreover, their distribution in the small bowel closely parallels the site of predilection of adenocarcinoma in human small bowel. Most commonly, however, these agents produce neoplasia in the colon. Tumors are found distally, again paralleling the usual distribution observed in humans. Macro-scopically, colonic tumors appear as polypoid masses or sessile plaques and invasion into and through the muscle coat occurs. Several histological varieties of carcinoma are observed but most are well-differentiated invasive adenocarcinomas. Administration of lower doses of carcinogen reportedly leads to an apparent shift in distribution to a more proximal colonic site.33 In proximal colon, tumors also develop although less frequently. Often, these are mucinous or colloid type adenocarcinomas similar to the distribution of this tumor in humans. In this type, extracellular mucus is found within cystic spaces of the tumor. A rarer signet ring cell type of carcinoma may also be found. In this form, mucus is observed within the cell displacing the nucleus peripherally. Sarcomas also may be found but carcinoid-type tumors have not been reported in this animal model. Morphological and biochemical alterations,48 as well as their similarities and differences to human disease are further detailed elsewhere in this monograph.
Pathology and Staging of Colorectal Adenoma and Adenocarcinoma
Peter Sagar, Andrew G. Hill, Charles H. Knowles, Stefan Post, Willem A. Bemelman, Patricia L. Roberts, Susan Galandiuk, John R.T. Monson, Michael R.B. Keighley, Norman S. Williams in Keighley & Williams’ Surgery of the Anus, Rectum and Colon, 2019
According to the WHO classification, it is estimated that more than 95% of colorectal cancers are adenocarcinomas.20 Conventional adenocarcinoma is characterised by glandular formation, which is the basis for tumour grading. Signet ring cell carcinoma has stage-independent adverse prognostic significance relative to conventional type adenocarcinoma,19 and it is defined by the presence of more than 50% of tumour cells showing signet ring cell features characterised by a prominent intracytoplasmic mucin vacuole that pushes the nucleus to the periphery.
Pancreatic Cancer
Dongyou Liu in Tumors and Cancers, 2017
Signet ring cell carcinoma is a malignant epithelial neoplasm showing predominantly infiltrating round non-cohesive (isolated) cells containing intracytoplasmic mucin. Before confirmation of a primary pancreatic signet ring carcinoma, there is a need to rule out metastases from a breast or gastric source.
Immunohistochemistry features and molecular pathology of appendiceal neoplasms
Published in Critical Reviews in Clinical Laboratory Sciences, 2021
Reger R. Mikaeel, Joanne P. Young, Gonzalo Tapia Rico, Peter J. Hewett, Jennifer E. Hardingham, Wendy Uylaki, Mehgan Horsnell, Timothy J. Price
MACs refer to tumors in which histologically extracellular mucin comprises >50% of the cross-sectional area. According to the PSOGI, primary appendiceal mucinous adenocarcinoma can be classified into well-differentiated, moderately differentiated, and poorly differentiated MACs. Well-differentiated MACs often consist of neoplastic epithelium with minimal nuclear atypia lining the cystic mucin pools, while poorly differentiated MACs show no or little gland formation [14]. However, the diagnostic criteria for these three descriptive terms are not provided by the PSOGI. Poorly differentiated (mucinous) adenocarcinoma with signet ring cells are defined as neoplasms in which signet ring cells are present in <50% of the cells. PMP patients with signet ring cells tend to be associated with poor prognosis, and therefore, this group of patients are classified separately [52–54]. Signet ring cell carcinoma refers to neoplasms in which signet ring cells are present in >50% of the cells in adenocarcinoma. In addition, primary appendiceal adenocarcinoma, which can be non-mucinous, resembles colorectal adenocarcinoma radiologically and histologically and is further classified into well-differentiated, moderately differentiated, and poorly differentiated non-mucinous adenocarcinoma. Most appendiceal adenocarcinomas are of the AMN subtype and frequently arise from LAMNs. However, these carcinomas have also been reported to arise from adenomatous polyps or/and serrated adenomas [1,55,56].
Incidentally found mucinous epithelial tumors of the appendix with or without pseudomyxoma peritonei: diagnostic and therapeutic algorithms based on current evidence
Published in Acta Chirurgica Belgica, 2021
Wim Ceelen, Marc De Man, Wouter Willaert, Gabrielle H. van Ramshorst, Karen Geboes, Anne Hoorens
Low-grade appendiceal mucinous neoplasms (LAMN) are characterized by a cytologically bland, usually single-layer epithelium, which may extend into the appendiceal wall by either broad-front pushing invasion or by dissection by acellular mucin into the wall (Table 1). Both result in perforation and intra-abdominal spread, giving rise to the PMP syndrome. High-grade appendiceal mucinous neoplasms (HAMN) behave similarly and do not exhibit infiltrative growth, but the neoplastic epithelium has unequivocal high-grade features such as cribriform growth, loss of polarity with full-thickness nuclear stratification, enlarged or hyperchromatic nuclei, and numerous or atypical mitotic figures. Adenocarcinomas of the appendix show infiltrative invasive growth and malignant behavior, including lymphatic and distant metastasis (Table 2). They can be mucinous (extracellular mucin comprising >50% of the tumor), mucinous with signet ring cells, or non-mucinous. If >50% of cells show signet ring morphology, the tumor is designated ‘signet ring cell adenocarcinoma’. Mucinous tumors of the appendix are graded according to a three-tiered grading system. Grade 1 tumors are LAMNs. HAMNs and conventional mucinous adenocarcinomas qualify as grade 2. Tumors with unequivocal signet-ring cells qualify as grade 3. Non-mucinous adenocarcinomas are graded using a two-tiered grading system, low-grade (formerly well- to moderately differentiated) and high-grade (formerly poorly differentiated), similar to non-appendiceal colorectal cancer.
Chemopreventive efficacy of juniper berry oil (Juniperus communis L.) on azoxymethane-induced colon carcinogenesis in rat
Published in Nutrition and Cancer, 2021
Turan Yaman, Ahmet Uyar, Ahmet Ufuk Kömüroğlu, Ömer Faruk Keleş, Zabit Yener
The production of mucin is a common histological feature in colorectal cancers. If more than 50% of the lesion consists of extracellular mucin, it is called a mucinous adenocarcinoma. This variant is characterized by accumulation of the extracellular mucin (39, 42). Signet ring cell mucinous carcinoma is a subtype of mucinous carcinoma that produces intracellular mucin (42). This subtype has a diffuse development pattern with few or no glands visible in microscopic terms. More than 50% of tumor cells have pronounced intracytoplasmic mucin. Intracellular mucin accumulation pushes the nucleus, creating a typical signet ring cell appearance. Metastasis of the lymph node, peritoneum, ovaries, and rarely the liver are observed (43, 44). In colon carcinoma, signet ring cell carcinoma can accompany other microscopic conditions at certain rates, and their presence and ratios must be specified in reports, as prognosis is quite poor (45). In this study, atypical epithelial cells with the signet ring cell appearance were detected in dense amounts in the cecum and ileocecal lymph nodes of a rat in the AOM group. However, this type of cell was not encountered in the AOM + JB group of rats.