181 gastric polyps obtained by endoscopic polypectomy were studied clinico-pathologically. The polyps occurred most frequently in the lower portion, and the incidence of the polyps tended to increase with age. 91% (164/181) of the polyps were occupied by hyperplastic polyps, and 3 polyps and one polyp respectively with dysplastic and carcinomatous foci were detected in 164 hyperplastic polyps. Although hyperplastic polyps rarely transform into dysplasia or carcinoma, careful follow-up is recommended

Hara Kohei

Haraguchi Masuo

Itsuno Minoru

Kawaziri Akihiro

Makiyama Kazuya

Matsunaga Keiitirou

Murata Ikuo

Oohi Junji

Sun Rui-Zhong

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Acta Med. Nagasaki 36:238-242A Clinico-pathological Study of Gastric Polyps    Treated with Endoscopic PolypestomyRui-Zhong SUN, Kazuya MAKIYAMA, Junji OOHI Minoru ITSUNO Ikuo MURATA, Kohei HARA 1) Keiitirou MATSUNAGA 2), Masuo HARAGUCHI 3)          and Akihiro KAWAZIRI 4)1) The Second Department of Internal Medicine, Nagasaki University   School of Medicine 2) Omura Municipal Hospital 3) Sasebo Municipal Hospital 4) National Ureshino HospitalReceived for publication, June 21, 1991SUMMARY : 181 gastric polyps obtained by endoscopic polypectomy were studied clinico-pathologically. The polyps occurred most frequently in the lower portion, and the incidence of the polyps tended to increase with age. 91% (164/181) of the polyps were occupied by hyperplastic polyps, and 3 polyps and one polyp respectively with dysplastic and carcinomatous foci were detected in 164 hyperplastic polyps. Although hyperplastic polyps rarely transform into dysplasia or carcinoma, careful follow-up is recommended.        INTRODUCTION  Endoscopic polypectomy has been performed safely in recent years, and it became possible to make detailed histopathological diagnosis. The hyperplastic polyp (HP), which is the most common type of the gastric polyp, was generally understood not to transform to malignancy.'' 2'. But some authors recently reported a few cases of malignant transformation of hyperplastic po-lyps3. 7)  In this paper, we studied clinico-pathological-ly 181 gastric polyps obtained by endoscopic polypectomy, and discussed malignant trans-formation of the gastric polyps.   MATERIALS AND METHODS  181 gastric polyps were obtained by endo-scopic polypectomy. After the specimens werefixed in 10% formalin, they were embedded in paraffin and then were cut. At last serial cut-sections were stained by hematoxilin and eosin.          RESULTS 1) Age distribution and sex ratio of polyps (Fig. 1)  The age distribution of the patients with the polyps ranged from 20 to 80 years. They oc-curred most frequently in the 7th decade. 2) Histopathological findings (Table 1)  181 polyps histologically consisted of 164 HPs (90.6%), 12 adenomas (6.6%), 2 adenocarcinomas (1.1%) and 3 inflammatory fibroid polyps (1.6%).  HPs consisted of hyperplastic foveolar epi-thelium with or without pyloric gland as-sociated with inflammatory infiltrates. Small foci of dysplastic epithelium at the superficial layers in three of 164 polyps and foci of well-differentiated adenocarcinoma in one of themTable 1. Histological Diagnosis of the Gastric         Polypoid Lesions Removed by Endo-         scopic Polypectomy       Histological Diagnosis Lesions (%) Hyperplastic polyp 160 (88.4) Hyperplastic polyp with dysplastic foci 3 ( 1.7) Hyperplastic polyp with focal carcinoma 1 ( 0.5) Adenoma 10( 5.5) Adenoma with focal carcinoma 2 ( 1.1) Adenocarcinoma 2 ( 1.1) Inflammatory fibroid polyp 3 ( 1.7)       Total 181Fig. 1. Age Distribution of Gastric Polypoid LesionFig. 3. a : Pieces of the hyperplastic polyp removed          by polypectomy.       b : A focus of well differentiated adenocar-         cinoma is seen in the piece of the hy-         perplastic polyp.Fig. 2 a : Dysplastic focus in the hyperplastic         polyp (arrow).       b : High power microscopic view of the dys-         plastic epithelium with stratification of         nuclei and an increase of N/C ratio.Table 2. Location of Gastric Polypoid Lesions Treated with Endoscopic PolypectomyThe location of 6 polypoid lesions were unknown 0: Hyperplastic polyp OO : Hyperplastic polyp with dysplastic foci ®: Hyperplastic polyp with focal carcinoma ,L : Adenoma A : Adenoma with focal carcinoma • : Adenocarcinoma 0: Inflammatory fibroid polypwere detected, preserving the border between the neoplastic and hyperplastic epithelium (Fig. 2 and Fig. 3). The dysplastic foci correspanded histologically to adenoma defined by Hirota$'. Two of 12 adenomas were also accompanied by foci of differentiated adenocarcinomas 3) Location (Table 2)  The location of gastric polyps was described according to "The General Rules for Gastric Cancer Study" which divided the stomach intothe upper portion (C), midportion (M) and lower portion (A), and into the anterior wall, posterior wall, lesser curvature and greater curvature.  The polyps were found most frequently in A area, and the incidence was 68.6% (120/175), and 28.6% (50/175) was found in M area and only 2.8% (5/175) in C area. 3 polyps showing ma-lignant change, one adenocarcinoma with adeno-matous pattern and 7 adenomas were found in A area, and 3 adenomas, one adenocarcinoma with adenomatous pattern and one hyperplasticTable 3. Size and Shape of Polypectomied Lesions Treated by EndoscopyO: Hyperplastic polyp (9 : Hyperplastic polyp with dysplastic foci • : Hyperplastic polyp with focal carcinoma L : Adenoma A : Adenoma with focal carcinoma • : Adenocarcinoma O: Inflammatory fibroid polyppolyp with dysplastic foci were found in M area.4) Relationship between macroscpic type and size (Table 3 )  The polyps were macroscopically classified according to Yamada's classification. The pol-yps of Type 4 (pedunculated type) were most frequantly found, and the incidence was 65.3% (115/176). The incidence of Type 3 (semiped-unculated type) was 26.7% (47/176), and that of type 1 and type 2 (sessile type) was 7.9% (14/176). And 84% (148/176) of Type 3 and Type 4 was hyperplastic polyps.  Of 115 polyps of Type 4, 72% (83/115) was over 1cm in diameter. In 14 polyps of Type 1 and Type 2, 71% (10/14) was under 1cm. Althouugh 45% (21/47) of 47 polyps of Type 3 was under lcm in diameter, 55% (26/47) was over 1 cm.         DISCUSSION  The most common type of the gastric polyps is the hyperplastic polyp compromising 88 to 96 % of all gastric polyps'), and the hyperplastic polyps tend to grow into Type 3 (semiped-unculated from) or Type 4 (pedunculated from). As shown in Table 2, 164 (90.4%) of 181 polyps were hyperplastic polyps, and 91% (145/162) of the polyps of Type 3 and Type 4 were hyper-plastic polyps. Pedunculated polyps tended to increase in number with the increase in size of polyps. Some studies showed that malignant transformation of the hypeplastic polyps as well as adenomas increased when they are more than 2 cm in diameterlo, 11, 12) Alothough the incidence of malignant transformation of themis low, hyperplastic polyps even less than 1 cm in diameter as shown in our data rarely showed maliganant change.  Malignant transformation of benign polyps is based on the histological criteria as follows : (1) malignant focus in the benign polyp, (2) remnant of the histological features characterized as the benign polyp, (3) malignant focus with sufficient cellular and structural atypia9' ' 3'. According to the criteria mentioned above, three focal carci-nomas were derived from one hyperplastic polyp and two adenomas. In our data, the rate of malignant transformation of 181 gastric pol-yps was 1.6% (3/181). Two hyperplastic polyps with dysplastic foci were also seen. The epi-thelium of hyperplastic polyp is capable of undergoing both neoplastic and kinetic alterna-tion. Some authors showed that the cancerous focus was derived from the dysplastic area in hyperplastic polyps rather than from non-dysplastic epithelium'). Therefore, careful fol-low-up is recommended even in hyperplastic polyps. The polyps occur most frequently in the lower portion mainly composed of antral mucosa, and the incidence of the polyps tended to increase with age, especially over 40 years old. This reault is in agreement with that reported by the other authors"). The occurrence of gastric polyps may be related to atrophic change and intestinal metaplasia advancing with age.         REFERENCES 1) Nagatomi, Y., Kawamura, S., Takeuchi, K., et    al: Polypous bud and its growth. Stomach and  Intestine 17 : 389 (1982) (Japanese). 2) Fukuchi, S., Hayakawa, K., Yamada, N., et al.:   Natural history of gastric polyps based on the    results of clinical follow-up study. Saishin Igaku   36: 55 (1981) (Japanese).3) Daibo, M., Itabashi, M., Hirota, T.: Maligant    Transformation of Gastric Polyps. Am. I Gas-   troenterol. 82 : 1016 (1987) 4) Yanbe, T., Sakashita, 0., Nagatomi, Y., et al.:    Symposium II. The follow-up study of gastric    polypoid lesion. Gastroenterol. Endosc. 24: 1462   (1981) (Jaoanese). 5) Mochizuki, F., Ueno, K., Hisamichi, S., et al.:    Cancerous change of gastric polyp. Stomach and   Intestine 10: 347 (1975) (Japanese). 6) Muto, T., Shimazu, H., Kobori, K., et al.: Ma-   lignant transformation of benign gastric polyps.   Stomach and Intestine 10: 341 (1975) (Japanese) 7) Remmele, W., Kolb, E. F.: Malignant transfor-   mation of hyperplastic polyps of the stomach.   Endoscopy 10: 63 (1987) 8) Hirota, T., Okada, T., Itabashi, M., et al.:    Histogenesis of human gastric cancer : With    special reference to the significance of adenoma    as a precancerous lesion. In: Ming SC, ed. Pre-   cursors of gastric cancer., p. 301. New York,    Philadelphia, Eastboune, Toronto Hong Kong,   Tokyo, and Sydney : Praeger Publishers 1984. 9) Nagayo, T.: Histological criteria of malignant    transfromation of gastric polyp and its results.   Stomach and Intestine 10: 301 (1975) (Japanese). 10) Hay, L. T.: Polyps and adenomas of the stom-  ach. Surgey 33: 446 (1953). 11) Monaco, A. P., Castleman, B., Roh, S. I., et al:    Adenomatatous polps of the stomach. Cancer   15: 456 (1962). 12) Kamiya, T., Morishita, T., Asakura, H., et al.:   Histological long standing follow up study of    hyperplastic polyps of the stomach. Am. I   Gastroenterol. 75 : 275 (1981). 13) Nakamura, T.: Malignant change of gastric    polyp, with special reference to histopathological   classification. Stomach and Intestine 3 : 737 (1968)   (Japanese).

A Clinico-pathological Study of Gastric Polyps Treated with Endoscopic Polypestomy

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A Clinico-pathological Study of Gastric Polyps Treated with Endoscopic Polypestomy

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