Histopathological Spectrum of Colorectal Polyps in a General Hospital

Abstract

Background  A colorectal polyp is a small mass that forms on the lining mucosa of the colon and rectum. Most of these polyps are harmless, but some of them may eventually turn into malignant tumors with a high mortality rate in later stages.

Objective  To analyze the histopathological spectrum of different colorectal polyps diagnosed at a tertiary care hospital via colonoscopy and to determine their association with the patients' age and gender to better understand their potential premalignant significance.

Materials and Methods  The current is a retrospective, cross-sectional study conducted at the Al-Kindy Teaching Hospital), in Baghdad, Iraq. Data were collected from 113 patients with colorectal polyps diagnosed via colonoscopy from 2014 to 2024. The patients underwent colonoscopy, and a biopsy was performed and sent for a histopathological study.

Results  The study sample presented a higher percentage of male (71.68%) compared to female patients (28.31%). Their ages ranged from 17 to 95 years, with a mean of 65 ± 2.92 years. The most common type of polyp was hyperplastic (27.43%), followed by adenomatous (tubulovillous; 23.89%), and the least common types were serrated polyps and those with malignant transformation (0.88% each).

Conclusion  Colorectal polyps are more prevalent among older adults, with a marked predominance in male subjects. In the present study most of them were asymptomatic, and the dominant histopathological subtype was adenomatous.

Keywords
colon; rectum; hyperplastic; adenomatous; polyp

Introduction

The term polyp is derived from the ancient Greek word polypous, meaning morbid lump, and it describes any mass protruding into the lumen of a hollow vessel, such the as gastrointestinal, genitourinary, and respiratory tracts.¹ Polyps usually originate from the mucosal layer of these organs, although some submucosal pathologies may cause mucosal protrusion into the lumen and resemble mucosal polyps.² Not all polyps necessarily exhibit neoplastic behavior. A colorectal polyp is one of a heterogeneous group of lesions with varying malignant potential, characterized by an asymptomatic disease that is discovered during colonoscopy or sigmoidoscopy, and it affects many individuals worldwide.³ These polyps can be defined as a small clump of epithelial tissues that protrude from the mucosal lining of the colon or rectum into the lumen.⁴ There are many risk factors that contribute to their development, such as aging, positive family history (familial adenomatous polyposis), genetic factors, lifestyle, high-fat diet, smoking, obesity, and lack of exercise.⁵ They are often harmless, benign, and asymptomatic, but they can cause symptoms like rectal bleeding, changes in bowel habits, abdominal pain, iron-deficiency anemia, and some of them have the potential to develop malignancy over time.⁶

Colorectal polyps can vary in size (small or large), shape (sessile or pedunculated with stalk), and histopathology (adenomatous precancerous, which have a potential to progress to carcinoma, hyperplastic benign, inflammatory, hamartomatous, and malignant).⁷ Therefore, early screening, detection, and removal of colorectal polyps using a colonoscope are essential. It is important to note that polyp detection should not rely on artificial intelligence, for this leads to deskilling among physicinas.⁸,⁹ It is also important to preventing progression to colorectal cancer, which remains a leading cause of cancer morbidity and mortality worldwide.¹⁰ Colon cancer is the second major type of tumor, with a mortality rate of approximately 10.2% according to the World Health Organization (WHO) Global Cancer Observatory.¹¹ Therefore, understanding the histopathological spectrum, risk factors, and clinical presentation of colorectal polyps is central for screening programs, for the planning of risk-stratification colonoscopy, and for the development of effective disease-prevention policies.¹² The aim of the present study was to evaluate the spectrum of histopathological types of colorectal polyp in a tertiary care hospital throughout 10 years.

Materials and Methods

The current is a retrospective, cross-sectional study conducted at Al-Kindy Teaching Hospital, in Baghdad, Iraq. Data were collected from 113 patients with colorectal polyps diagnosed via colonoscopy from 2014 to 2024. The study was approved by the Scientific and Ethical Committee of Al-Kindy College of Medicine, University of Baghdad, and Al-Kindy Teaching Hospital. The inclusion criteria were patients with symptoms of rectal bleeding, abdominal pain, altered bowel habits, and asymptomatic patients who discovered the polyp accidentally during colonoscopy. The exclusion criteria were patients with gastrointestinal or colorectal malignancy, history of partial or total colectomy, rectal resection, hemorrhoids, inflammatory bowel disease, familial polyposis syndromes, and systemic diseases affecting the morphology of the colon. The patients underwent colonoscopy, which was performed by trained gastroenterologists, and their biopsies were performed either by mucosal or submucosal resection of a polyp from the inner lining of the colon or rectum (polypectomy), or using a wire loop (snare), without an electrical current (cold), to remove polyps by mechanical transection without the use of electrocautery. These biopsies were sent for a histopathological study. The specimens were fixed in 10% neutral buffered formalin, processed, embedded in paraffin, and cut into thin sections. The sections were then stained with hematoxylin and eosin (H&E) and examined under a light microscope. Then, the histopathological spectrum of these specimens was analyzed, and they were classified as follows: hyperplastic, adenomatous (tubular, villous, or tubulovillous), inflammatory, hamartomatous, and serrated. The degree (high or low) of epithelial dysplasia was also assessed, as well as identify malignant transformation.

Statistical Analysis

The data collected were analyzed using Excel (Microsoft Corp.), and the IBM SPSS Statistics for Windows (IBM Corp.) software. Descriptive statistics were used regarding the continuous variables, which were expressed as mean ± standard deviation (SD) values, while the categorical variables were expressed as frequencies and percentages. The Chi-squared (χ²) test was used to assess the associations involving the categorical variables, such as polyp type, location, and histopathological findings. Values of p lower than 0.05 were considered statistically significant.

Results

The present cross-sectional, retrospective study included 113 patients with colorectal polyps. The sample presented a higher percentage of male (71.68%) compared to female patients (28.31%) (p = 0.000). Their ages ranged from 17 to 95 years, with a mean of 65 ± 2.92 years. Most of the patients were from Baghdad (95%), and the rest, from other provinces (5%) (p = 0.000). Most of the subjects were asymptomatic (61.94%), with their polyps discovered during colonoscopy, and the rest (30%) presented with complaints of rectal bleeding, abdominal pain, mucous discharge, and altered bowel habits (p = 0.000) (Table 1). Table 2 shows the most common type was hyperplastic (27.43%; (Fig. 1), followed by adenomatous (tubulovillous; 23.89%; Fig. 2). The least common types were serrated and polyps with malignant transformation (0.88% each). On histopathological type that was not detected was hamartomatous planes-risk stratification. The rate of inflammatory polyps was of 10.61% (Fig. 3)

Table 1
Demographic characteristics of the study sample

Characters		n	%	p-value
Male patients		81	71.68	≤ 0.001
Female patients		32	28.31
Mean age (years)		65 ± 2.92
Baghdad residents		107	95.00	≤ 0.001
Residents of other Iraqi provinces		6	5.00
Asymptomatic subjects		70	61.94	≤ 0.001
Symptomatic subjects (rectal bleeding, abdominal pain, mucous discharge, and altered bowel habits)		43	38.05
Polyp location	Colon	83	73.45	≤ 0.001
	Rectum	20	17.69
	Colon and rectum	10	8.84
Polyp type	Pedunculated	34	30.08	≤ 0.001
	Sessile	79	69.91

Table 2
Distribution of types within the histopathological spectrum of colorectal polyps

Histopathological type		nr.	%		p-value
Hyperplastic non-malignant		31	27.43		≤ 0.001
Adenomatous with dysplasia	Tubular	15	13.27	54.85
	Villous	20	17.69
	Tubulovillous	27	23.89
Inflammatory		12	10.61
Hamartomatous		0.00	0.00
Serrated		1	0.88
Degree of epithelial dysplasia	Low grade	4	3.53
	High grade	2	1.76
Malignant transformation	Positive	1	0.88		≤ 0.001
	Negative	112	99.11
Total		113

Fig. 1
Hyperplastic polyp characterized by bland-looking colonic crypts with a saw-tooth configuration (arrows). No L- or T-shaped crypts were observed, distinguishing it from a sessile serrated lesion (hematoxylin and eosin [H&E]; magnification – right: 4×; left: 10×).

Fig. 2
Tubulovillous adenoma characterized by tubules and villi lined by hyperchromatic, pseudostratified, pencil-shaped nuclei. The arrow points to area of loss of polarity, confirming focal high-grade dysplasia (H&E; magnification – right: 4×; left: 10×).

Fig. 3
Inflammatory polyp characterized by inflammatory lamina propria with bland-looking colonic crypts. The arrows point to multiple dilated crypts filled by aggregate of neutrophils (crypt abscesses) (H&E; magnification – right: 4×; left: 10×).

Discussion

Most of the 113 patients with colorectal polyps in the present study were male subjects (71.7%) with a mean age of 65 years. These findings align with the variety mentioned in international studies¹³ regarding male predominance (since the polyp detection rates are higher among men, and they have approximately 1.4 to 1.5 times the chance of developing polyps compared to women), as well as with the well-established rise in polyp prevalence with age. Most patients were residents of Baghdad (95%), which is also in agreement with other studies that have shown colorectal cancer is more common in urban than in rural areas, while survival rates are lower in rural areas due to delayed diagnosis and limited access to health care screening programs. Studies¹⁴ have shown that higher levels of colorectal polyps are found in urban areas due to lifestyles involving poor diets and inactivity.

Regarding the clinical presentation of this disease in the present study, 61.9% of the subjects were asymptomatic upon presentation, and the rest complained of rectal bleeding, abdominal pain, and altered bowel habits, which in agreement with another study¹⁵ In the current study, the polyps were found more often in the colon than the rectum (73.5% versus 17.7%), and the lesions were more commonly sessile than pedunculated (69.9% versus 30.1%), which is generally consistent with findings that polyps are frequently detected throughout the colon, with the sigmoid colon often reported as the most common site, followed by the rectum or other colonic segments. The distribution can vary among studies and populations, but overall, the colon typically presents more polyps than the rectum.¹⁶ Histologically, adenomatous lesions, which include tubular, villous, and tubulovillous lesions, comprised most of the polyps (54.85%) found in the current study, while hyperplastic polyps accounted for 27.4%, inflammatory polyps, for 10.6%, and serrated lesions were rare (0.9%), which is a favorable finding, as these lesions are recognized precursors to colorectal cancer, particularly the sessile and flat types located on the right side of the colon, which are often difficult to detect and may be challenging to completely resect. This is in line with several studies and cohorts reports in which adenomas formed the largest histological subgroup, with a prevalence of 50 to 60%. This supports the conclusion that, in this population, the dominant neoplastic pathway was adenoma that led to carcinoma.¹⁷

The second most common type was hyperplastic polyps, which made up about a quarter of the lesions in the present study, a finding also comparable to those of multiple established studies.¹⁸ Moreover, the location of the polyps in the current study reported colon whether proximal or distal part of the it was predominance over rectal polyps. The results reported vary in terms of the distribution of polyps, with some studies showing a higher rectal or sigmoid frequency, and others showing colon predominance. These differences may be due to the patterns of patient referrals, colonoscopy training, and practice, as well as the ages of the patients involved in the study. The present study's finding of a predominance of colonic location is consistent with those of several other studies.¹⁹

Another important finding was that the rate of sessile lesions was of approximately 70%. This type of lesion is hard to detect; moreover, it may lead to a dysplastic pathology, and it is difficult to resect through endoscopy. This underlines the need for careful inspection techniques, high-quality bowel preparation, chromo- or pan-endoscopic enhancement where available, and a skillful polypectomy to decrease the risk of missed or incompletely-removed lesions.¹² The low frequency of high-grade dysplasia (1.8%) and very low malignant transformation rate (0.9%) in the current study align with other reports that show that most polyps detected through screening present low-grade dysplasia. Large screening studies²⁰ have documented low malignancy rates among small polyps and low rates of high-grade dysplasia in polyps smaller than 1 cm, although the risk increases with increasing size, villous histopathology, and advanced patient age. These findings support our conventional interpretation that most colorectal polyps detected are premalignant rather than malignant. The present study supports the need to expand screening programs, especially in high-risk populations. Further studies with larger sample sizes and multicenter participation are recommended to improve the generalizability of the findings and evaluate the long-term outcomes.

Limitations

The current is a single-center series with a modest sample size, and referral bias toward Baghdad residents, which limits generalizability. There was a lack of detailed data on polyp size and endoscopic resection margins, as well as of follow-up that relates morphology and histology to recurrence and progression.

Conclusion

The present study demonstrated that colorectal polyps are asymptomatic, more prevalent among older male adults. Adenomatous polyps remain the dominant histopathological subtype, and most lesions are premalignant, with low immediate malignant transformation rates.

• Funding
  The authors declare that they did not receive funding from agencies in the public, private, or non-profit sectors to conduct the present study.

Data Availability

Data will be available upon request to the corresponding author.

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Edited by

• Editor-in-Chief:
  Henrique Sarubbi Fillmann.

Publication Dates

• Publication in this collection
  17 July 2026
• Date of issue
  2026

History

• Received
  22 Dec 2025
• Accepted
  08 Apr 2026