Polypoidal lesions of the gastrointestinal tract

Background: With increasing usage of endoscopic procedures, gastrointestinal polypoidal lesions are commonly encountered specimens. Histopathological examination is crucial as biological behavior is dependent on its pathological nature. Materials and Methods: A retrospective descriptive study performed in Pathology department, Om Hospital and Research Centre from January 2017 to June 2019. The study included lesions received as polyp or polypoidal lesions of gastrointestinal tract for histopathological examination. Data was analysed using SPSS version 17.0. Gender, number and site were analysed using Chi square test to evaluate its association with neoplastic nature. Correlation with age and size was tested with Pearson’s correlation coefficient. Results: Among 150 cases of gastrointestinal tract polypoidal lesions, 58% were seen in male and 42% in female. Hyperplastic polyp and conventional adenoma were the commonest non-neoplastic and neoplastic lesions respectively. The age of patients ranged from 7 to 84 years with a mean age of 50 years. Rectosigmoid region was the commonest site. 134 patients had single and 16 had multiple polypoidal lesions. Most polypoidal lesion had size <1 cm. Gender, age, number and size showed no correlation with neoplastic nature. A significant association was found with site with notably higher number of neoplastic lesions in large intestine. Conclusion: A spectrum of histological types of polypoidal lesions were found in gastrointestinal tract, most frequently in colorectal region. Hyperplastic polyp and adenomatous polyp were the commonest non-neoplastic and neoplastic lesions respectively. A notably higher number of polypoidal lesions in the large intestine were found to be neoplastic in nature. ABSTRACT


INTRODUCTION
Gastrointestinal (GI) polypoidal lesions are nodules or mass that project above the level of surrounding mucosa and protrudes into the lumen. They may arise as a result of epithelial or stromal cell hyperplasia, inflammation, ectopia and neoplasia. 1 They may occur anywhere in the GI tract but are most common in the colorectal region. [1][2][3] With increasing usage of endoscopic procedures, GI polypoidal lesions are commonly encountered specimens in histopathology practice.
Chi square test to evaluate its association with neoplastic nature. The correlation with continuous variables (age and size of polypoidal lesion) was tested with the help of Pearson's correlation coefficient. The level of significance was set at 5 percent.

RESULTS
Of the 150 cases of GI tract polypoidal lesions, 87 (58%) were seen in male and 63 (42%) in female with a male to female ratio of 1.4:1. Gender wise distribution of the various histological types of polypoidal lesions is illustrated in figure 1. Majority (117 cases, 78%) of the lesions were nonneoplastic and 33 cases (22%) were neoplastic. Hyperplastic polyp (55 cases, 37%) and conventional adenoma (29 cases, 19%) were the commonest non-neoplastic and neoplastic polypoidal lesions respectively (Table 1).
Amongst the conventional adenomas, 25 had tubular and four had tubulovillous morphology. High grade dysplasia was noted in three of these cases. The age of the patients ranged from 7 to 84 years with a mean age of 50 years. The mean age for the neoplastic and non-neoplastic category was 54 and 48 years respectively. Maximum number of cases 31 (21%) was noted in 41-50 years age group followed by 30 (20%) cases in 51-60 years age group (Table  2). Rectosigmoid region was the commonest site (56 cases, 37.5%) followed by colon (35 cases, 23.5%) and stomach (32 cases, 21.5%). The most frequently found polyp in stomach and rectosigmoid region was hyperplastic polyp, in duodenum foveolar metaplastic polyp and conventional adenoma in colon. There were two cases of neuroendocrine tumor grade 1, one in duodenum and other in recto-sigmoid location (Table 3). 134 patients had single polypoidal lesion and multiple lesions were noted in 16 patients. The size of the polypoidal lesion was <1 cm in 136 cases, 1-1.9 cm and ≥ 2 cm in 7 cases each.
Analysis of gender, number, size of polypoidal lesions and age of the patient with categories of neoplastic versus non-neoplastic was not statistically significant. However, a significant association (p=0.008) was found with the site of polypoidal lesions, with notably higher number of neoplastic lesions in the large intestine (Table 4 and 5).

DISCUSSION
A notably higher number of GI polypoidal lesions were found in males compared to females corroborating data from various studies. 3,7-9 Majority (n=117, 78%) of the polypoidal lesions in our study were non-neoplastic. This finding is consistent with that of a study performed in Nepal by Gurung et al in which 70% GI polyps were nonneoplastic. 2 In contrast, neoplastic polypoidal lesions were more prevalent in studies performed by Manakkad et al in India and Mirzaie et al in Iran. 7,9 Polypoidal lesions with malignant potential are classified as neoplastic whereas non-neoplastic ones have none or lesser possibility of malignant transformation. 3 The presence or potential risk of malignancy in these polypoidal lesions is the key concern. 4 The size and site of the polyp and age of the patient are found to be significant risk factors for development of malignancy. [5][6][7] Histopathological examination is crucial as the biological behavior is dependent on its pathological nature.
This study aims to assess the prevalence and histological nature of polypoidal lesions of the GI tract received at histopathology department of Om Hospital and Research Centre, Kathmandu, Nepal. It evaluates the age, gender and anatomical site wise distribution as well as number and size of the polypoidal lesions. Further the association of patient factors (age and gender) and characteristics of polypoidal lesion (number, size and site) with neoplastic nature is analysed. This study could help us gain an insight into the clinico-pathological characteristics of polypoidal lesions of the GI tract in the Nepalese population.

MATERIALS AND METHODS
This is a retrospective descriptive study conducted in the Department of Pathology at Om Hospital and Research Centre, Kathmandu, Nepal. The study included all lesions identified endoscopically as polyp or polypoidal lesion of the gastrointestinal tract which was biopsied and received at histopathology laboratory for examination. The study sample comprised of 150 polypoidal lesions of the GI tract received over a period of two and half years from January 2017 to June 2019. All the relevant data were retrieved from the archived reports and entered and coded in an excel sheet. The data variables were histopathology number, age, gender, histopathological diagnosis, anatomical site, number and size of the polypoidal lesions. Analysis of the data was performed using SPSS version 17.0. The variables were summarized using mean, percentage and range. The data was represented with tables and bar diagram. Gender, number and site of polypoidal lesions were analysed using to be most prevalent. 2,10,11 This differing result may be due to the predominance of paediatric population in their studies. 2.5% of patients in this study were less than 20 years and juvenile polyp constitutes 7% of the lesions unlike the study of Khajuria et al with 54% cases less than 20 years. In their study juvenile polyp constituted 48% of the cases. 11 The age of the patients ranged from 7 to 84 years with a mean age of 50 years. This finding is in accordance with studies of Chitturi et al 3 and Manakkad et al. 7 The age of the patients ranged from 4 to 88 years with a mean age of 46.59 years in study of Chitturi et al. 3 Manakkad et al found mean age of 47.14 years with age range of 2-85 years. 7 A lower mean age was observed in studies with larger volume of paediatric patients. 11 More than half the cases in our study was noted in 41-60 years age group, comparable to Sharma In the present study, adenomatous polyp was the commonest neoplastic polyp which is comparable to other studies. 2,7,9,10 Amongst them, 25 (86%) had tubular and four (14%) had tubulovillous morphology. High grade dysplasia was noted in three (10.3%) of the cases. This finding is similar to many studies which showed predominance of tubular subtype with prevalence varying from 70.3% to 77% and high grade dysplasia ranging from 8.6% to 21.43%. 2,9,11 Invasive adenocarcinoma in adenomatous polyp was reported ranging from 2.85% to 5.6%. 10,12 However, component of invasive adenocarcinoma was not seen in our study. Among the non-neoplastic polyps, hyperplastic polyp (55 cases, 37%) was the most common followed by inflammatory (23 cases, 15%) and juvenile polyp (10 cases, 7%). Similar result pattern was noted by Sharma et al. 13 This finding, however, is different from many studies which found juvenile polyp    Adenomatous, inflammatory and juvenile polyps constituted the major bulk of remaining colorectal polyps. One of the inflammatory polyp was associated with ulcerative colitis and remaining were non-specific. There were two cases of neuroendocrine tumor grade 1, one in duodenum and other in recto-sigmoid location. 134 patients had single polypoidal lesion and multiple lesions were noted in 16 patients. The size of the polypoidal lesion was <1 cm in 136 cases, 1-1.9 cm and ≥ 2 cm in 7 cases each. Chitturi et al found most of the polyps in their study to be less than 1 cm. 3 et al. 13 Jayadevan et al found that there was a five-fold increase in the prevalence of colonic polyps over age 40. 14 Rectosigmoid region was the commonest site (56 cases, 37.5%) followed by colon (35 cases, 23.5%). This is in agreement with the literature which highlights that colorectal polyps are the most frequently encountered GI polyps. 9,10 Our study showed low incidence of oesophageal polyps (n=3, 2%), which coincides with various studies. 9,10 Site wise, the most common polypoidal lesions were squamous papilloma in oesophagus, hyperplastic polyp in stomach and colorectal region and gastric foveolar metaplastic polyp in duodenum. Hyperplastic polyp and adenomatous polyp was found to be the commonest polyp in stomach and colorectal region resepectively in studies of Gurung et al, Mirzaie et