Studies On Clinical And Pathological Features Of Gastric Polypoid Lessions

Background: In past decades, as the wide usages and improvement of endoscopic techniques, gastric polypoid lesions have been quite frequently found. Except for chronic gastritis and gastric cancer, the gastric polyps have become the commonly used terms in clinical diagnosis. However, there exist some controversies about diagnosis and differential diagnosis of the gastric polyps. First, almost all the polypoid lesions protuberant on gastric mucosa are all diagnosed as gastric polyps. In fact, pathologically, these lesions include gastric polyps, inflammation diseases, and even malignant tumors. The real gastric polyps are relatively few. Thus, the accordance between clinical diagnosis and pathological diagnosis has been quite unsatisfactory. Sencond, there is still no generally accepted histological classification and diagnostic criteria for the gastric polyps. And lack of systematic study on gastric polyps is the third problem. The etiology, biological feature and long-term effects of the gastric polyps are still not clear enough.To further elucidate the biological features of gastric polyps, the clinical and pathological features of 789 gastric polypoid lesions cases were retrospectively analyzed and the immunohistochemical phenotype of CKs and Ki-67 of gastric polyps was evaluated in this study.Part I Clinical features and pathological analysis endoscopic gastric polypoid lesions in 789 cases Objective:To determine the accordance rate between clinical diagnosis and pathological diagnosis by observing the endoscopic and pathomorphological features of gastric polyps and to summarize the pathological features and classifications of gastric polyps for Chinese population.Methods1 CasesDuring the period between October 1996 and October 2008, a total 789 patients (311 men, 478 women, mean age 51.89 years) who were diagnosed as gastric polyps (as the following gastric polypoid lesions ) by endoscopic examination at Second Hospital of Hebei Medical University were included in this series. Among them, 661 cases were with single polyps and 128 cases with multiple cases (Familial adenomatous polyposis was excluded).2 Clinical feature analysis of the single gastric polypoid lesions casesThe clinical data, including location, size and shape of gastric polypoid lesions was analyzed in 661 cases. All the cases were diagnosed as gastric polyps by endoscopic examination.3 The pathological diagnosis of gastric polypoid lesions According to the diagnostic criteria of gastric polyp, "diagnostic pathology, 2nd edition ", edited by Liu Tong Hua, all slides of 789 cases were reviewed by two experienced pathologists to analyze the pathological charcteristics of gastric polypoid lesions and confirm the diagnosis. The accordance rate between clinical diagnosis and pathological diagnosis was determined to evaluate the possible differences in endoscopic features between gastric polyps and non-gastric polypic lesions. 4 Statistical methodsThe data were evaluated by aχ2 test with significance accepted at a value of P <0.05.Results1 The clinical features of single gastric polypoid lesions Out of 661 cases of single gastric polypoid lesions, 88 cases (13.3%) were located in the cardia, 102 cases (15.4%) in fundus, 146 cases (22.1%) in gastric body, and 325 cases (49.2%) in antrum. The results showed that single gastric polypoid lesions mainly occurred in the antrum.According to the long diameter in 661 cases of single gastric polypoid lesions, the percentage for the cases≤0.5cm, 0.5cm ~ 2.0cm, 2.0cm ~ 3.0cm and > 3.0cm was 53.7%, 41.8%, 2.7%, and 1.8% respectively. On the whole, 95.5% (631/661) of cases were≤2.0cm in the diameter.Morphologically, among the 661 cases of single gastric polypoid lesions, 590 cases could be classified as Yamada type I, and 15 cases, type II, 24 cases, type III and 32 cases type IV. It showed that Yamada type I was the mainly type in morphology. 2 The pathological feature of single gastric polypoid lesions Among the 661 cases of gastric polypoid lesions dignosed by endoscope, only 231 (34.9%) cases could be diagnosed as gastric polyps based on the pathological diagnostic criteria of gastric polyps. Except gastric polyps, inflammatory lesions accounted for 62.6% (414 cases). The other cases were adenocarcinoma (5 cases), leiomyoma (4 cases), stromal tumor (3 cases), heterotopic pancreas (3 cases), and inflammatory granulation tissue (1 case).Thus, the results in this study suggestted that among the gastric polypoid lesions diagnosed as gastric polyps with endoscopic examination, inflammation account for the most of cases, only 34.9% could be diagnosed as gastric polyps pathologically.3 The classification and endoscopic features of gastric polyps Among the 789 cases, 231 could be diagnosed as gastric polyps, according to the diagnostic criteria of Liu Tong Hua" diagnostic pathology, 2nd edition" Histologically, 157 cases were hyperplastic polyps (68.0%), 63 cases, fundic gland polyps (27.3%), 7 cases, adenomatous polyps (3.0%) and the other 4 cases were inflammatory fibroid polyps (1.7%). Thus, it suggested that hyperplastic polyps be the most frequent histological type in this series of gastric polyps.By the frequences of sub-site, the gastric hyperplastic polyps could be found in the following order: antrum (39.6%), cardia (29.9%), body (22.9%) and fundus (7.6%). The distribution in long diameter of polyps were 0.5cm～2.0cm (52.2%),≤0.5cm (38.9%), 2.0cm～3.0cm (6.4%), >3.0cm (2.5%). According to Yamada classification, the gastric hyperplastic polyps could be classified as typeⅠ(76.4%), typeⅡ(5.7%), typeⅢ(7.6%), typeⅣ(10.3%).The percetage of fundic gland polyps occurred at fundus was 55.6%, body, 41.3%, and antrum, 3.1%. The polps≤0.5cm in long diameter accounted for 66.7% and 0.5cm～2.0cm, 33.3%. According to Yamada classification, the gastric fundus polyps could be classified as typeⅠ(92.1%), typeⅢ(4.8%), typeⅣ(3.1%).Adenoma found at fundus, body and antrum was 14.3%, 14.3% and 71.4% respectively. The polyps 0.5cm～2.0cm in long diameter were most commonly seen one (57.1%), while that≤0.5cm and 2.0cm～3.0cm accounted for 28.6% and 14.3% respectively. The most common Yamada classification type was type I (71.4%),followed by type III (14.3%) and type IV (14.3%).Three cases of inflammatory fibroid polyps occurred at antrum and the other one in body. According toYamada classification, three cases were 75% of type I and the other one type IV.4 The comparison of gastric polyps and non-gastric polypic lesions in clinical featuresThe percetage of non-gastric polypic lesions found at antrum, body, fundus and cardia was 58.8%, 19.1%, 12.6% and 9.5% respectively, while that for the gastric polyps was 49.2%, 22.1%, 15.4% and 20.3% respectively. It suggested that the sub-site distribution of gastric polyps be more equal among body, fundus and cardia (χ2=48.246, P=0.000).The percetage of polyps≤0.5cm, 0.5cm～2.0cm, >3.0cm and 2.0cm～3.0cm in long diameter for non-gastric polypic lesions was 57.9%, 39.1%, 1.6% and 1.4% respectively, while that for gastric polyps was 46.8%, 45.9%, 5.2% and 2.2%. It suggested that the mean long diameter of gastric polyps is larger than that in non-gastric polypic lesions (χ2=14.371, P=0.002).Yamada Type I account for 94.0% of the non-gastric polyps lesions, while that for the gastric polyps was 80.5% (χ2=28.487, P=0.000). Part II The immunohistochemical study of different types of gastric polypsObjective:To observe the expression of Ki-67, CK7/CK20 in different types of gastric polyps and to explore the proliferation and differentiation feature for different types of gastric polyps.Methods1 CasesA total of 73 samples were obtained from 68 patients (29 men, 44 women; aged 21 ~ 81 years). Among the 68 cases, 63 cases were with single polyps and 5 cases with multiple polyps. And 53 cases was hyperplastic polyps, 5 cases ,fundic gland polyps, 11 cases, adenomas and 4 cases, inflammatory fibroid polyps. The sub-site location included cardia (12 cases), gastric fundus (5 cases), gastric body (29 cases) and antrum (27 cases). Fifteen cases of normal gastric tissue specimens taken from trauma or ulcer gastric resection specimen were also selected as control.2 Immunohistochemistry staining With immunohistochemical EliVisionTMplus two-step method, the expression of Ki-67, CK7/CK20 was studied. The result of Ki-67 was determined according to the labeling index, while CK7 and CK20 was assessed as negative or positive according to the immunostaining.3 Statistical analysisThe experimental data were statistically analyzed by t- test, one-way ANOVA, nonparametric rank sum test, with statistics software of SPSS14.0 edition. Results1 The expression of Ki-67 in gastric polyps and normal gastric mucosaThe immunoreaction of Ki-67 locates in the nuclei. In normal gastric mucosa tissues, Ki-67 positive expression is limited to the bottom of gastric pit and glandular neck with low LI. Except inflammatory fibroid polyps, Ki-67 positive expression was seen in all types of gastric polyps with varying degrees.The mean labeling index of Ki-67 in all the gastric polyps is 0.4119±0.3108, while in normal gastric mucosa, 0.2493± 0.0535. Significance differences are found between the two groups (P=0.000).Among different gastric polyps, the mean labeling index of Ki-67 is 0.7864±0.2703 for adenoma, 0.3966±0.2560 for hyperplastic polyps, 0.0800±0.0903 for fundic gland polyps, 0 for inflammatory fibroid polyps. The mean labeling index of Ki-67 for adenoma is significantly higher than that of the other three gastric polyps (P<0.05). There is no significant difference in Ki-67 expression between fundic gland polyps and inflammatory fibroid polyps (P>0.05).2 The expression of CK7/CK20 in gastric polyps and normal musocaThe positive reaction of CK7 and CK20 locates in cytoplasm as brown granules. There is no positive expression of CK7 in normal gastric mucosa. CK20 was uniformly expressed in surface epithelial cells in normal gastric mucosa but not in deep glands. The positive reaction of CK7 and CK20 could be found in different types of gastric polyps except inflammatory fibroid polyps.The immunohistochemical phenotype of CK7/CK20 in gastric polpys included CK7+/CK20+ in 58/73 (79.5%), CK7-/CK20- in 4/73 (5.5%), CK7+/CK20- in 6/73 (8.2%), CK7-/CK20+ in 5/73 (6.8%) and CK7-/CK20- in 4/73 (5.5%). Thus, the results showed that immunohistochemical phenotype of CK7+ /CK20 + is the important feature for gastric polyps except inflammatory fibroid polyps. There is no significant difference in gastric hyperplastic polyps and gastric fundic gland polyps, gastric hyperplastic polyps and gastric adenoma in the immunohistochemical phenotype of CK7/CK20. There is also no significant differences in immunohistochemical phenotype of CK7/CK20 among different sub-site location (χ2=1.082 P=0.781).Conclusions1 The gastric polypoid lesions could be found mainly in the antrum, and 95.5% were≤2.0cm in long diameter and typeⅠfor Yamada classification.2 The majority of gastric polypoid lesions are inflammation diseases, only 34.9% of cases could be pathologically diagnosed as gastric polyps.3 The hyperplastic polyps are more frequently found in the antrum with the long diameter range from 0.5 to 2.0cm. Fundic gland polyps are more in the gastric fundus and body with the size of≤0.5cm in long diameter. Gastric adenomas were mainly found in the antrum. The mean labeling index of Ki-67 for adenoma is significantly higher than that of the other three gastric polyps (P<0.05).4 The immunohistochemical phenotype of CK7+/CK20+ is one of the important features in gastric polyps.